ON SUBSTANCES THAT DEPLETE

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1 MONTREAL PROTOCOL ON SUBSTANCES THAT DEPLETE THE OZONE LAYER UNEP 2010 REPORT OF THE REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS TECHNICAL OPTIONS COMMITTEE 2010 Assessment

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3 UNEP 2010 REPORT OF THE REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS TECHNICAL OPTIONS COMMITTEE 2010 ASSESSMENT

4 Montreal Protocol On Substances that Deplete the Ozone Layer UNEP 2010 REPORT OF THE REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS TECHNICAL OPTIONS COMMITTEE 2010 ASSESSMENT The text of this report is composed in Times New Roman. Co-ordination: Composition: Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee Lambert Kuijpers (Co-chair) Formatting, Reproduction: UNEP Nairobi, Ozone Secretariat Date: February 2011 No copyright involved Printed in Kenya; 2011 ISBN iv 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report

5 DISCLAIMER The United Nations Environment Programme (UNEP), the Technology and Economic Assessment Panel (TEAP) co-chairs and members, the Refrigeration AC and Heat Pumps Technical Options Committee, cochairs and members, and the companies and organisations that employ them do not endorse the performance, worker safety, or environmental acceptability of any of the technical options discussed. Every industrial operation requires consideration of worker safety and proper disposal of contaminants and waste products. Moreover, as work continues - including additional toxicity evaluation - more information on health, environmental and safety effects of alternatives and replacements will become available for use in selecting among the options discussed in this document. UNEP, the TEAP co-chairs and members, the Refrigeration, AC and Heat Pumps Technical Options Committee, co-chairs and members, in furnishing or distributing this information, do not make any warranty or representation, either express or implied, with respect to the accuracy, completeness, or utility; nor do they assume any liability of any kind whatsoever resulting from the use or reliance upon any information, material, or procedure contained herein, including but not limited to any claims regarding health, safety, environmental effect or fate, efficacy, or performance, made by the source of information. Mention of any company, association, or product in this document is for information purposes only and does not constitute a recommendation of any such company, association, or product, either express or implied by UNEP, the Technology and Economic Assessment Panel co-chairs or members, the Refrigeration, AC and Heat Pumps Technical Options Committee co-chairs or members, or the companies or organisations that employ them. ACKNOWLEDGEMENT The UNEP Refrigeration, A/C and Heat Pumps Technical Options Committee acknowledges with thanks the outstanding contributions from all of the individuals and organisations who provided technical support to committee members. In developing this report, particularly the chapter lead authors were instrumental. The names of chapter lead authors, co-authors and contributors are given at the start of each chapter. Addresses and contact numbers of the chapter lead authors and all other authors of the UNEP TOC Refrigeration, A/C and Heat Pumps can be found in Annex I. The opinions expressed are those of the Committee and do not necessarily reflect the views of any sponsoring or supporting organisations. Gratitude is expressed to UNEP s Ozone Secretariat, Nairobi, Kenya for the co-operation in formatting and styling of the report and for the reproduction of this report TOC Refrigeration, A/C and Heat Pumps Assessment Report v

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7 UNEP 2010 REPORT OF THE REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS TECHNICAL OPTIONS COMMITTEE 2010 ASSESSMENT Table of Contents KEY MESSAGES...XII ABSTRACT EXECUTIVE SUMMARY...1 EXECUTIVE SUMMARIES OF ALL CHAPTERS INTRODUCTION MONTREAL PROTOCOL DEVELOPMENTS THE UNEP TECHNOLOGY AND ECONOMIC ASSESSMENT PANEL THE TECHNICAL OPTIONS COMMITTEE REFRIGERATION, A/C AND HEAT PUMPS REFRIGERATION, AIR CONDITIONING AND HEAT PUMPS General Remarks Long Term Options and Energy Efficiency Set up of the 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report REFRIGERANTS INTRODUCTION Refrigerant Progression Unsaturated Hydrofluorochemicals DATA SUMMARY Ozone Depletion Potentials ODP and GWP Data for Regulatory and Reporting Purposes STATUS AND RESEARCH NEEDS FOR DATA Thermophysical Properties Heat Transfer and Compatibility Data Safety Data REFERENCES DOMESTIC REFRIGERATION INTRODUCTION OPTIONS FOR NEW EQUIPMENT Refrigerant Options Not-In-Kind Alternative Technologies Product Energy Efficiency Improvement Technologies OPTIONS FOR EXISTING EQUIPMENT Drop-In Conversion of In-Service Products END-OF-LIFE CONSERVATION AND CONTAINMENT CONCERNS CURRENT REFRIGERANT USE New Equipment Production Field Service Future Refrigerant Demand Implications Future Refrigerant Emission Implications REFERENCES TOC Refrigeration, A/C and Heat Pumps Assessment Report vii

8 4 COMMERCIAL REFRIGERATION INTRODUCTION APPLICATION Equipment and Systems OPTIONS FOR NEW EQUIPMENT Stand-Alone Equipment Condensing Unit Systems Supermarket Systems OPTIONS FOR EXISTING EQUIPMENT REFERENCES INDUSTRIAL SYSTEMS INTRODUCTION APPLICATIONS (INCLUDING SIZE OF MARKET, CURRENT PRACTICE, REGIONAL VARIATIONS) Food Processing Cold Storage Industrial Cooling in Buildings and IT Centres Industrial Heat Pumps and Heat Recovery Leisure Process Refrigeration WORKING FLUID OPTIONS FOR NEW EQUIPMENT R-717 (Ammonia) Hydrofluorocarbons HCFC Hydrocarbons R-744 (Carbon dioxide) R-718 (Water) Absorption RETROFIT OPTIONS FOR EXISTING EQUIPMENT Conversion to HFC Blends Conversion to R Conversion to R Conversion to Hydrocarbon OVERVIEW OF REFRIGERANT CONSUMPTION, BANKS AND EMISSIONS SERVICE REQUIREMENTS REFERENCES TRANSPORT REFRIGERATION INTRODUCTION TECHNICAL PROGRESS Merchant, Naval and Fishing Vessels Road Transport Railcars Intermodal Containers Small Containers and Boxes REFRIGERANT OPTIONS FOR EXISTING EQUIPMENT REFRIGERANT OPTIONS FOR NEW EQUIPMENT RECOVERY, REUSE AND DESTRUCTIONS OF REFRIGERANTS BANK AND EMISSION DATA REFERENCES AIR-TO AIR AIR CONDITIONERS AND HEAT PUMPS INTRODUCTION APPLICATIONS Small Self-Contained Air Conditioners Non-ducted (or duct-free) Split Residential and Commercial Air Conditioners Ducted, Split Residential Air Conditioners Ducted Commercial Split and Packaged Air Conditioners CURRENT USE OF HCFC viii 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report

9 7.3.1 Small Self-Contained Air Conditioners Non-ducted Split Air Conditioners Ducted, Split Residential Air Conditioners Ducted Commercial Split and Packaged Air conditioner HCFC-22 Bank OPTIONS FOR NEW EQUIPMENT Methodology Single Component HFC Refrigerants HFC Blends Reduced GWP HFC Refrigerants and Blends Hydrocarbon Refrigerants R Flammability Considerations Not-in-Kind Alternative Technologies OPTIONS FOR EXISTING EQUIPMENT Service Blend Refrigerants Retrofit Refrigerants Anticipated Market Impact of Drop-in and Retrofit Refrigerants Hydrocarbons as Conversion/Drop-in Refrigerants HIGH AMBIENT CONSIDERATIONS R-410A in High Ambient Applications HC-290 in High Ambient Applications R-407C in High Ambient Applications HFC-32 in High Ambient Applications HFC-134a and HC-600a in High Ambient Applications R-744 in High Ambient Applications HFC Replacements for High Ambient Applications REFERENCES WATER HEATING HEAT PUMPS INTRODUCTION TYPES OF HEAT PUMPS Heat Pump Water Heaters (HPWH) Space Heating Heat Pumps Combined Space and Hot Water Heat Pumps Capacity Ranges of Water and Space Heating Heat Pumps HEAT PUMP IMPLICATIONS AND TRENDS Trends of Heat Pumps Replacing From Gas or Fuel Burning System CO 2 Heat Pump Water Heaters CURRENT REFRIGERANT OPTIONS FOR WATER AND SPACE HEATING HEAT PUMPS HCFC HFC-134a and HFC blends R-407C and R-410A Hydrocarbons R-744 (Carbon Dioxide) R-717 (Ammonia) FUTURE REFRIGERANT OPTIONS FOR NEW HEAT PUMPS HFC-134a and HFC Blends R-407C and R-410A HFC HFC-1234yf and Other Low-GWP HFC Blends R-744 (Carbon Dioxide) Hydrocarbons R-717 (Ammonia) REFERENCES CHILLERS FUNCTION OF CHILLERS TYPES OF CHILLERS Mechanical Vapour-Compression Chillers Absorption Chillers TOC Refrigeration, A/C and Heat Pumps Assessment Report ix

10 9.2.3 Chiller Capacity Ranges DEVELOPMENTS AND TRENDS IN CHILLER MARKETS Measures of Chiller Efficiency or Energy Use Developments in the Market Vapour-Compression Chillers Developments in the Market Absorption Chillers CURRENT REFRIGERANT CHOICES AND OPTIONS FOR MECHANICAL VAPOUR-COMPRESSION CHILLERS Positive Displacement Chillers Centrifugal Chillers REFRIGERANT OPTIONS FOR NEW CHILLER EQUIPMENT Options for New Positive Displacement Chillers Options for New Centrifugal Chillers Issues with HCFC-123, HFC-134a, R-410A, and Other HFC Chiller Refrigerants Alternatives to Vapour Compression Systems (Absorption Chillers) OPTIONS FOR EXISTING CHILLER EQUIPMENT Positive Displacement Chillers Centrifugal Chillers Not-in-Kind Chiller Replacements Absorption BANKS AND EMISSIONS RELATING TO CHILLERS REFERENCES VEHICLE AIR CONDITIONING INTRODUCTION Regulatory Actions affecting Vehicle Air Conditioning and Refrigerants TECHNICAL PROGRESS EXISTING MOBILE AIR CONDITIONING SYSTEMS HFC-134a Retrofit of CFC-12 systems OPTIONS FOR FUTURE MOBILE AIR CONDITIONING SYSTEMS Passenger Car and Light Truck Air Conditioning Bus and Rail Air Conditioning REFERENCES REFRIGERANT CONSERVATION INTRODUCTION RECOVERY, RECYCLING, AND RECLAMATION REFRIGERANT RECOVERY AND RECYCLING EQUIPMENT TECHNICIAN TRAINING AND SERVICE CERTIFICATION REFRIGERANT RECLAMATION, SEPARATION, DESTRUCTION Reclamation and Separation EQUIPMENT DESIGN AND SERVICE Design Charge Minimising Installation Servicing Reduction of Emissions through Leak Tightness DIRECT REGULATION AS A MEANS OF REFRIGERANT CONSERVATION Financial Incentives Required Service Practices and Leak Tightness Restrictions on the sales and imports of ODSs END-OF-LIFE EXAMPLES OF CONSERVATION APPROACHES Africa South America China United States Japan ARTICLE 5 ISSUES REFERENCES x 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report

11 ANNEX 1 AUTHORS, CO-AUTHORS AND CONTRIBUTORS TO THE 2010 RTOC REPORT ANNEX 2: - EXCERPT OF THE FINAL REPORT ON GLOBAL INVENTORIES OF THE WORLDWIDE FLEETS OF REFRIGERATING AND AIR-CONDITIONING EQUIPMENT IN ORDER TO DETERMINE REFRIGERANT EMISSIONS. THE 1990 TO 2006 UPDATING TOC Refrigeration, A/C and Heat Pumps Assessment Report xi

12 Key messages The required global phase-out of HCFCs, and the need to manage the lifetime operation of CFC- and also HCFC-based equipment, coupled with concerns to reduce global warming, drive transition from ozone depleting substance (ODS) refrigerants. The technical options are universal, but local laws, regulations, standards, economics, competitive situations and other factors influence regional and local choices. More than 60 new refrigerants, many of them blends, were introduced for use either in new equipment or as service fluids (to maintain or convert existing equipment) since the 2006 assessment report. The primary focus for examination of new refrigerants is on unsaturated hydrofluorocarbons and unsaturated hydrochlorofluorocarbons. The overarching climate change issue as well as changing refrigerant options for refrigeration and air conditioning will continue to advance equipment innovations. HFCs and non-fluorochemical options are increasingly used in most sectors, with emphasis on optimising system efficiency (expressed as Coefficient of Performance - COP) and reducing emissions of high Global Warming Potential (GWP) refrigerants. There are several low and medium GWP alternatives being considered as replacements for HCFC-22. These include lower GWP HFC refrigerants (HFC-32, HFC-152a, HFC-161, HFC- 1234yf and other unsaturated fluorochemicals, as well as blends of them), HC-290 and R-744 (CO 2 ). HC-290 and some of the HFC refrigerants are flammable and will need to be applied in accordance with an appropriate safety standard. A high degree of containment applies to all future refrigerant applications, either for decreasing climate impact or for safety reasons. The latter aspect will also increase the need to advance charge reduction technologies. In commercial refrigeration stand-alone equipment, hydrocarbons (HCs) and R-744 are gaining market shares in Europe and in Japan; they are replacing HFC-134a, which is the dominant choice in most countries. In many developed countries, R-404A and R-507A have been the main replacements for HCFC-22 in supermarkets, however, because of their high GWP, a number of other options are now being introduced. Indirect systems are the most effective option for emissions reductions in new centralised systems for supermarkets. In two stage systems in Europe, R-744 is used at the low-temperature level and HFC-134a, R-744 and HCs at the medium temperature level. In industrial refrigeration, R-717 (ammonia) and HCFC-22 are still the most common refrigerants; R-744 is gaining in low-temperature, cascaded systems where it primarily replaces R-717 (ammonia), though the market volume is small. In air-to-air air conditioning, HFC blends, primarily R-410A, but to a limited degree also R- 407C, are still the dominant near-term replacements for HCFC-22 in air-cooled systems. HC- 290 is also being used to replace HCFC-22 in low charge split system, window and portable air conditioners in some countries. Most Article 5 countries are continuing to utilise HCFC-22 as the predominant refrigerant in air conditioning applications. Up to now, car manufacturers and suppliers have evaluated several refrigerant options for new car (and truck) air conditioning systems including R-744, HFC-152a and HFC-1234yf, all with GWPs below the EU threshold of 150. These options can achieve fuel efficiency comparable to the existing HFC-134a systems with appropriate hardware and control development. The use of hydrocarbons or blends of hydrocarbons has also been considered but so far has not received support from vehicle manufacturers due to safety concerns. The eventual decision which refrigerant to select for vehicle air conditioning will be made based on the GWPs of the above three options along with additional considerations including regulatory approval, costs, system reliability, safety, heat pump capability and servicing. xii 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report

13 Abstract Executive Summary Current status The required global phase-out of HCFCs, and the need to manage the lifetime operation of CFC- and also HCFC-based equipment, coupled with concerns to reduce global warming, drive transition from ozone depleting substance (ODS) refrigerants. The technical options are universal, but local laws, regulations, standards, economics, competitive situations and other factors influence regional and local choices. The primary current solutions are summarised below. Refrigerants: More than 60 new refrigerants, many of them blends, were introduced for use either in new equipment or as service fluids (to maintain or convert existing equipment) since the 2006 assessment report. The primary focus for examination of new refrigerants is on unsaturated hydrofluorocarbons and unsaturated hydrochlorofluorocarbons. Additional refrigerants are still being developed to enable completion of scheduled phase-outs of ODSs. Significant focus is on alternatives, including blend components, offering lower global warming potentials (GWPs) to address climate change, forcing more attention than in the past on flammable or low-flammability candidates. Research continues to increase and improve the physical, safety, and environmental data for refrigerants, to enable screening, and to optimise equipment performance. Domestic refrigeration: The conversion of new equipment production to the use of non-ods refrigerants is essentially complete. More than one-third of newly produced units globally now use the refrigerant HC-600a; the balance uses HFC-134a. CFC emissions from the 150,000 tonnes domestic refrigerant bank are dominated by end-of-life disposal due to the high equipment reliability. Approximately 70% of the current, residual CFCs reside in Article 5 countries. Commercial refrigeration: Hydrocarbons (HCs) and R-744 (CO 2 ) are gaining market shares for standalone equipment in Europe and in Japan; they are replacing HFC-134a, which is the dominant choice in most non-article 5 and Article 5 countries. For condensing units and supermarket systems, the largest refrigerant bank consists of HCFC-22, which represents about 60% of the global commercial refrigerant bank. In developed countries, the replacement of HCFC-22 in supermarkets is dominated by R-404A and R-507A, however, a number of other options are used. In Europe, R-744 is used at the low-temperature level and HFC-134a, R-744 and HCs at the medium temperature level as alternatives to R-404A and R-507A because of their high GWP. Industrial refrigeration: R-717 and HCFC-22 are the most common refrigerants for new equipment; cost considerations have driven small new systems to HFC use. R-744 is gaining in low-temperature, cascaded systems where it primarily replaces R-717 (ammonia), though the market volume is small for such systems. The ODS refrigerant bank consists of 20,000 tonnes of CFCs and 125,000 tonnes of HCFCs and HFCs. Annual ODS emission rates are in the range of 10-25% of the total banked refrigerant charge. R-717 remains the primary refrigerant in large industrial systems, especially those for food and beverage processing and storage. Transport refrigeration: HCFC-22 has a low share in intermodal containers and road equipment, a high share in railcars (declining market) and a very high share in marine vessels. Today, virtually all new systems utilise HFC refrigerants (R-404A and HFC-134a). Non-fluorinated refrigerants have been commercialised to a small extent aboard marine vessels (R-717, R-744), and tested in marine containers, trailers (R-744) and trucks (HC-290). The refrigerant banks are estimated at 2,700 tonnes of CFCs and 27,200 tonnes of HCFC-22. The annual leak rate is in the range of 20-40%, depending on the specific application. Air-to-air conditioners and heat pumps: HFC blends, primarily R-410A, but to a limited degree also R-407C, are still the dominant near-term replacements for HCFC-22 in air-cooled systems. HC-290 is also being used to replace HCFC-22 in low charge split system, window and portable air conditioners 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 1

14 in some countries. Most Article 5 countries are continuing to utilise HCFC-22 as the predominant refrigerant in air conditioning applications. The refrigerant bank for unitary air conditioners is in excess of 1 million tonnes of HCFC-22. Water-heating heat pumps: Air-to-water heat pumps have experienced significant growth in Japan, Australia, China, and Europe during the last five years, especially owing to the government incentives in Europe and Japan, and in the USA in prior years. HCFC-22 is currently mainly used in Article 5 countries. The HFC blends R-410A and R407C are currently used in European and other countries. R-744 heat pump water heaters were introduced to the market in Japan in 2001 and have seen a steady growth since then, again influenced by significant subsidies. HC-290 is being applied but its use in Europe has decreased due to the introduction of the Pressure Equipment Directive. R-717 is mainly used for large capacity heat pump systems. Chillers: HCFC-22 has been phased out in new equipment in the developed countries, but is still used in Article 5 countries. Both HCFC-123 and HFC-134a are used in centrifugal chillers. HFC-134a and R-410A are the most common options in smaller systems with scroll and screw compressors; limited R-407C usage is dropping. The application of HCs and R-717 in chillers is less common and extremely rare as a fraction of the total in large chillers. Vehicle air conditioning: Today all new AC equipped passenger cars world-wide use HFC-134a; the transition from CFC-12 is complete for new systems, but not in old cars still in use especially in Article 5 countries. About one fifth of the total global refrigerant emissions are from Mobile Air Conditioning systems (about 60 percent if only HFC refrigerant emissions are considered); this includes the emissions in production, use, servicing, and end-of-life. Up to now, car manufacturers and suppliers have evaluated several refrigerant options for new car (and truck) air conditioning systems including R-744, HFC-152a and HFC-1234yf. These three options have GWPs below the EU threshold of 150 and can achieve fuel efficiency comparable to the existing HFC-134a systems with appropriate hardware and control development. The use of hydrocarbons or blends of hydrocarbons has also been considered but so far has not received support from vehicle manufacturers due to safety concerns. Most new bus or train air conditioning systems are currently equipped with the refrigerants HFC-134a or R-407C; fleet tests of R-744 systems in buses are ongoing. What is left to be achieved More than 100 refrigerants, including blends, are marketed at present, though approximately 20 consitute the overwhelming majority on a global basis and even that quantity is expected to fall as users converge on preferred options over time. Refrigerant manufacturers are in process of developing new candidates while equipment manufacturers are testing, selecting, and qualifying new refrigerants as well as associated lubricants and other materials. The technological options for air conditioning and refrigeration are expected to evolve over the next several years as designers continue to replace HCFC-22 with non-ods alternatives and focus on developing lower GWP alternatives for R-410A and R-407C. There are several low and medium GWP alternatives being considered as replacements for HCFC-22. These include lower GWP HFC refrigerants (HFC-32, HFC-152a, HFC-161, HFC- 1234yf and other unsaturated fluorochemicals, as well as blends of them), HC-290 and R-744. HC- 290 and some of the HFC refrigerants are flammable and will need to be applied in accordance with an appropriate safety standard such as IEC , which establishes maximum charge levels and ventilation requirements. Several commercial chains have made good progress on the containment of refrigerant in supermarket systems. Indirect systems are the most effective option for emissions reductions and, in Europe, are gaining market share in new centralised systems for supermarkets. Technical development of alternatives in industrial refrigeration is expected to emphasise R-717 and R-744 in the near future. A significant amount of research, development and testing will be required before unsaturated HFCs can be deployed in large industrial systems, and even then their high refrigerant price will be an impediment to adoption. In heat pumps for water heating, further development of the lower GWP TOC Refrigeration, A/C and Heat Pumps Assessment Report

15 options is expected. In transport refrigeration, a rapid phase-out of remaining HCFCs due to the relatively short life span of intermodal containers, railcars and road vehicles (10-15 years) and marine vessels (< 25 years) is expected. Depending on the CO2 emissions associated with the electricity production and the energy efficiency of the systems, there is a large potential to reduce CO 2 emissions generated by fossil fuel operated heating systems by replacing them with heat pumps. The decision which refrigerant will be eventually selected for vehicle air conditioning will be made based on additional considerations along with the Global Warming Potential of the current alternative options (R-744, HFC-152a, and HFC-1234yf); these include regulatory approval, costs, system reliability, safety, heat pump capability and servicing. World-wide, a significant amount of installed refrigeration equipment still uses CFCs and HCFCs. As a consequence, service demand for CFCs and HCFCs will continue. Refrigerant demand for service needs can be minimised by preventive service, containment, recovery, and recycling. Management of the CFC and HCFC banks in developing countries is an important issue. A critical step to address the refrigerant conservation topics above is thorough training of installers and service technicians, together with certification and regulation. Countries where programs have been successful have had comprehensive regulations requiring recovery and recycling, or destruction of refrigerant. The way forward The overarching climate change issue as well as changing refrigerant options for refrigeration and air conditioning will continue to advance innovations in this type of equipment. Many of the lower GWP refrigerant options are flammable, which increases the need to advance charge reduction technologies. HFCs and non-fluorochemical options are increasingly used in most sectors, with emphasis on optimising system efficiency (COP) and reducing emissions of high-gwp refrigerants. A high degree of containment applies to all future refrigerant applications, either for decreasing climate impact or for safety reasons. The competitive market is likely to result in refrigerant options for all common applications and either specialty products or equipment adaptation to accommodate new refrigerants for all applications, but the initial indications are that reduced efficiency is likely in several key uses. It is worth noting that manufacturing for refrigeration, air-conditioning, and heat pump equipment for export is increasing and is expected to increase further in Article 5 countries. In domestic refrigeration, and to a lesser extent in commercial stand-alone equipment, an emerging trend is conversion from HFC-134a to HC-600a. Non-Article 5 countries completed the conversion from ODS refrigerants in domestic refrigeration approximately 15 years ago; older equipment now approaches the equipment useful lifetime; this results in non-article 5 countries having a vanishing ODS refrigerant demand. The service demand for ODS refrigerants for domestic refrigeration in Article 5 countries is expected to remain strong for more than 10 years as a result of their later conversion to non-ods refrigerants. In commercial stand-alone equipment in Article 5 countries, the use of HCs is expected to increase. For two-temperature centralised systems, R-744 is an option for the lower temperature level; in the near future, there will be the choice for the medium-temperature level for new low GWP HFCs on the one hand and R-744 or HCs on the other. In industrial refrigeration, there are substantial banks of CFCs in Article 5 countries and HCFCs in both non- Article 5 and Article 5 countries that need addressing. Article 5 countries moving away from HCFCs (HCFC-22) might transfer to saturated HFCs, unsaturated HFCs if proven for use in industrial systems, to R-717 and R-744, or to other not-in-kind solutions. In transport refrigeration, HFCs will replace HCFCs and become a dominant refrigerant on passenger vessels and on small ships of all categories. The industry is working towards the use of non-fluorinated refrigerants in marine containers, trailers (R-744) and trucks (R-290); both are currently in the development and testing stage. In air-to-air air conditioning and heat pumps, HFCs, HFC blends and HC-290 are the most likely near-term refrigerants to replace HCFC-22 in most air conditioning applications. Contrary to non-article 5 countries, the demand for service refrigerants in most Article 5 countries will consist of HCFC-22 and HFC-based service blends; this tendency is driven by long equipment life and is also due to the costs of the field conversion to alternative refrigerants. In heat pumps for water heating, HFC-32 or unsaturated HFCs such as HFC-1234yf or blends with this refrigerant will be studied for 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 3

16 future use by taking into account the performance, costs and the necessary safety regulations in relation to their mild flammability. The front running candidate among global car manufacturers for future vehicle air conditioning systems seems to be HFC-1234yf. One manufacturer has announced the intention to introduce this refrigerant in car serial production in OEMs indicate that they will design HFC-1234yf MAC systems in such a way that these systems can safely be used with HFC- 134a refrigerant as well TOC Refrigeration, A/C and Heat Pumps Assessment Report

17 Executive Summaries of All Chapters Chapter 2: Refrigerants More than 60 new refrigerants were introduced for use either in new equipment or as service fluids (to maintain or convert existing equipment) since the 2006 assessment report. Significant focus is on alternatives, including blend components, offering lower global warming potentials (GWPs) to address climate change. That pursuit forces more attention than in the past on flammable or low-flammability candidates. Most of the new refrigerants are blends containing hydrofluorocarbons (HFCs) or in some cases blends of HFCs and hydrocarbons (HCs), the latter typically added to achieve miscibility with compressor lubricants to facilitate lubricant return to compressors. Additional refrigerants including blend components still are being developed to enable completion of scheduled phase-outs of ozone-depleting substances (ODSs). They include unsaturated fluorochemicals with primary focus on unsaturated HFCs and hydrochlorofluorocarbons (HCFCs), also identified as hydrofluoro-olefin (HFO) and hydrochlorofluoro-olefin (HCFO) compounds. Considerable effort continues for examination of broader use of ammonia, carbon dioxide, and HCs. Research continues to increase and improve the physical, safety, and environmental data for refrigerants, to enable screening, and to optimise equipment performance. The report updates and expands summary data for assessment of the new refrigerants as well as comparison to refrigerants already retired or being replaced as ODSs or for other environmental, performance, or safety reasons. The environmental data included are consistent with the 2010 WMO Scientific Assessment supplemented with additional data, to fill voids, from other consensus assessments and published studies. The new assessment updates the tabular data summaries from prior assessments. The revised data reflect consensus assessments and published scientific and engineering literature where possible. The summaries address refrigerant designations, chemical formulae, normal boiling point (NBP), critical temperature (T c ), occupational exposure limits, lower flammability limit (LFL), safety classification, atmospheric lifetime (t atm ), ozone depletion potential (ODP), global warming potential (GWP), and control status. The updated chapter also summarises the ODP and GWP values prescribed for regulatory reporting. The status of data for the thermophysical properties of refrigerants, which include both thermodynamic properties (such as density, pressure, enthalpy, entropy, and heat capacity) and transport properties (such as viscosity and thermal conductivity), is generally good for the most common and alternative refrigerants. Data gaps exist, however, for the thermodynamic and transport properties of blends and less-common fluids as well as for the transport properties of many fluids (but especially so for blends and for some of the new unsaturated fluorochemicals and blends containing them). The data situation for the less-common fluids is more variable; there is a need to collect and evaluate the data for such candidates. Significant research still is needed, but is not expected to retard scheduled ODS phase-outs. A major uncertainty for all of the refrigerants is the influence of lubricants on properties. The working fluid in most systems is actually a mixture of the refrigerant and the lubricant carried over from the compressor(s). Research on refrigerant-lubricant mixtures is continuing. The need for further studies is driven by the introduction of new refrigerants, by the great variety of lubricants in use and being introduced, and by the often highly proprietary nature of the chemical structures of the lubricant and/or additives. This chapter summarises data for refrigerants and specifically those addressed in subsequent sections of this assessment report. It discusses thermophysical (both thermodynamic and transport) properties as well as heat transfer, compatibility, and safety data TOC Refrigeration, A/C and Heat Pumps Assessment Report 5

18 This chapter does not address the suitability, advantages, and drawbacks of individual refrigerants or refrigerant groups for specific applications; such discussion is addressed for specific applications where relevant in subsequent chapters. The updated chapter reviews the status heat transfer and compatibility data for refrigerants. It recommends further research of: test data for shell-side boiling and condensation of zeotropic mixtures local heat transfer data determined at specific values of vapour quality microchannel heat exchanger refrigerant-side heat transfer data including flow distribution effects effects of lubricants on heat transfer, especially for ammonia, carbon dioxide, hydrocarbons, unsaturated HCFCs, and unsaturated HFCs more accurate evaporation and condensation data for hydrocarbons for both plain tube and enhanced tubes inside-tube condensation heat transfer data for carbon dioxide at low temperatures such as 20 C heat transfer correlations for carbon dioxide supercritical heat rejection and two-phase evaporation Chapter 3: Domestic Refrigeration Conversion of new domestic refrigerator production to non-ods refrigerants is essentially complete. Broad-based refrigerant alternatives continue to be HC-600a and HFC-134a. In 2008, 36% of production units used HC-600a or a binary blend of HC-600a and HC-290; 63% used HFC-134a. The remaining 1% used regionally available refrigerants, such as HFC-152a. Second generation non-ods refrigerant conversion from HFC-134a to HC-600a is complete in Japan and has begun in the United States and other countries. Significant extension of this second generation conversion is expected over the next decade. By 2020 it is estimated that three-fourths of refrigerant demand for new refrigerator production will be for HC-600a and one-fourth will be for HC-134a. No new technologies have surfaced which are cost and efficiency competitive with current vapour-compression technology. Service conversion to non-ods refrigerants has significantly lagged original equipment conversion. The distributed, individual-proprietor character of the service industry resists co-ordinated refrigerant management efforts. Field service procedures typically use originally specified refrigerants. Non- Article 5 countries completed new production conversion from ODS refrigerants approximately 15 years ago. This time span is approaching the useful equipment lifetime so service of ODS refrigerant containing products is transitioning to a sunset issue in these countries. Service demand for ODS refrigerants in Article 5 countries is expected to remain strong for more than ten years as a result of their later conversion to non-ods refrigerants. Unless there is governmental intervention, service demand for CFC-12 refrigerant is expected to continue. Enhanced product energy efficiency provides benefit to reduced global warming during the use phase of the refrigerator life cycle. Existing state-of-the-art models contain multiple, mature efficiency improvement options. Extension of these to all global products would yield significant benefits, but realisation will be constrained by capital funds availability. In 2006 the global domestic refrigerant bank was estimated to be 153,000 tonnes consisting of 40% CFC-12, 54% HFC-134a and 6% HC-600a. The bank is equally divided between non-article 5 and Article 5 countries. An estimated 71% of residual CFCs reside in Article 5 countries. Annual emissions from this bank were estimated to be 6.8%. The majority of domestic refrigerators never require sealed system service. Consequently, emissions are dominated by end-of-life product TOC Refrigeration, A/C and Heat Pumps Assessment Report

19 disposition; inferring legacy product emission management may be the largest opportunity for emission avoidance. Chapter 4: Commercial Refrigeration Commercial refrigeration comprises three different families of systems: centralised systems installed in supermarkets, condensing units installed mainly in small shops and stand-alone units installed in all types of shops. The refrigerant choices depend on the levels of conservation temperatures and the type of systems. The number of supermarkets world-wide is estimated to 280,000 in 2006 covering a wide span of sales areas varying from 400 m2 to 20,000 m2. The populations, in 2006, of vending machines and other stand-alone equipment are evaluated to 20.5 and 32 million units, respectively, and condensing units are estimated to 34 million units. In 2006, the refrigerant bank was estimated at 340,000 tonnes and was distributed as follows: 46% in centralised systems, 47% in condensing units, and 7% in standalone equipment. The estimated sharing of refrigerant per type is about 15% CFCs which are still in use in Article 5 countries, 62% HCFCs the dominant refrigerant bank and still for many years, and 23% HFCs which have been introduced in new equipment in Europe and Japan as of Stand-alone Equipment: HFC-134a fulfils most technical constraints in terms of reliability and energy performance for stand-alone equipment. When GWP of HFC-134a is considered prohibitive in relation to HFC emissions (country regulation or company policy), hydrocarbon refrigerants (isobutane and propane, i.e. HC-600a and HC-290) or CO 2 (R-744) are the current alternative solutions, presenting in most of the cases the same technical reliability and energy performance as HFC-134a. In the near future, unsaturated HFCs such as HFC-1234yf could be considered as an adapted solution, since the retrofit from HFC-134a to this new refrigerant is expected being rather simple, even if long term reliability has to be assessed. Energy efficiency standards are being issued or revisited in order to lower energy consumption of various types of stand-alone equipment. Condensing Units: Their cooling capacities vary from 5 to 20 kw mostly at medium temperature. The refrigerant charge varies from 1 to 5 kg for HCFCs or HFCs and also HCs. HCFC-22 is still the most used refrigerant in the U.S. and in all Article 5 countries. For new systems, R-404A is the leading choice for cost reasons; the condensing units using the refrigerant R-404A are cheaper compared to HFC-134a units of the same cooling capacity because of smaller compressor. Nevertheless in hot climate and for medium temperature applications, HFC-134a is used due to its better energy performances at high ambient temperatures. Supermarket systems: The size of centralised systems can vary from refrigerating capacities of about 20 kw to more than 1 MW related to the size of the supermarket. Refrigerant charges range from 40 up to 1500 kg per installation. The dominant refrigerant used in centralised systems is still HCFC-22. In Europe, new systems have been mainly charged with R-404A, but HFC-134a, ammonia (R-717), HCs and R-744 have been tested in many stores. R-744 is now considered off the shelf solution by the two major European manufacturers. Several designs have been experimented in hundreds of stores: distributed systems, indirect systems, cascade systems. Those designs have been developed in order to reduce the refrigerant charge to use more easily flammable or toxic refrigerants, or to limit the charge of high GWP HFCs. At the low temperature level the use of R-744 appears as an interesting option in terms of GWP, energy efficiency and even costs especially when HFCs are highly taxed. At the medium level temperature, the search for the best option is still ongoing. In the near term, servicing of current HCFC-22 may pose a problem due to possible shortage of this refrigerant. Several HFC blends are proposed to retrofit HCFC-22 installations with or without oil change, but those retrofit blends have not gained until now a significant momentum TOC Refrigeration, A/C and Heat Pumps Assessment Report 7

20 Chapter 5: Industrial Systems Industrial systems are characterised primarily by the size of the equipment and the temperature range covered by the sector. This includes industrial cooling, industrial heat pumps and industrial airconditioning. Industrial systems have special design requirements, including the need for uninterrupted service, which are not typically provided by traditional HVAC practices. Rankine cycle electrical generation systems using relevant fluids are also considered in the industrial systems chapter. R-717 is the most common refrigerant in industrial systems, although with significant regional variations around the world. Where R-717 is not acceptable for toxicity reasons, R-744 has been used, either in cascade with a smaller R-717 plant, in cascade with a fluorocarbon or rejecting heat direct to atmosphere in a high pressure ( transcritical ) system. In some cases, for example freezers or IT equipment cooling, R-744 offers additional advantages in performance or efficiency which merit selection ahead of any other refrigerant without consideration of toxicity or environment. There is also a significant bank of HCFC refrigerant in industrial systems, particularly HCFC-22. Individual system charge can be high in some cases several tonnes of refrigerant. These systems tend to have longer life than commercial equipment, often lasting over 20 years, but leakage rates can be high, particularly in older plants. A drop-in blend for replacing HCFC-22 in flooded industrial systems has not been developed; the common replacement blends used in commercial refrigeration such as R-407A or R-422D are difficult or impossible to use in large industrial systems. The cost of these blends is also a significant barrier to their use. HFCs have not been widely used in large industrial systems. Where they have been adopted it is generally in low charge systems in order to reduce the financial consequences of refrigerant loss. It is very unlikely that unsaturated HFC refrigerants, whether single compounds or blends, will be adopted for use in industrial systems because in addition to cost considerations the risk of refrigerant decomposition due to the presence of contaminants is too great. HFC-245fa and HFC-134a have also been used in power generation units, utilising the Rankine cycle, although these systems are not yet widely available on the market. Users of HCFCs in smaller industrial systems are now faced with the choice of whether to switch to HFCs and face a possible phase-down, or to change to R-717 or R-744 and deal with the change in operating practices that those refrigerants would require. Chapter 6: Transport Refrigeration Transport refrigeration includes transport of chilled or frozen products by means of road vehicles, railcars, intermodal containers, and small insulated containers (less than 2 m 3 ) and boxes. It also includes use of refrigeration and air conditioning on merchant, naval and fishing vessels above 100 gross tonnes (GT) (about over 24 m in length). Transport refrigeration is a niche market in terms of refrigerant banks compared to other sectors. There are about 4,000,000 road transport refrigeration units, and about 950,000 marine container units in operation today, to mention the largest segments in terms of fleet size. Most equipment has a refrigerant charge below 6 kg. Although refrigerant charge can reach several tons aboard large vessels, their fleet is relatively small. There are approx. 150,000 marine vessels above 100 GT in the world fleet; thereof small and medium size vessels have the largest share. The equipment lifetime is usually between 10 and 15 years for intermodal containers, railcars and road vehicles, and 20 to 25 years for equipment aboard marine vessels. The vapour compression cycle is the technology used predominantly in transport refrigeration equipment. CFC and HCFC refrigerants can be found in older equipment. HCFC-22 has a low share in TOC Refrigeration, A/C and Heat Pumps Assessment Report

21 intermodal containers and road equipment, but a high share in railcars (declining market) and a very high share in marine vessels, where it remains to be the dominant refrigerant. The CFC and HCFC banks have been decreasing. Retrofit options to R-502 include R-408A, R-402A and R-404A. Virtually all new systems utilise HFC refrigerants (HFC-134a, R-404A). Non-fluorinated refrigerants have been commercialised to a small extent aboard marine vessels (R-717, R-744), and tested in marine containers, trailers (R-744) and trucks (R-290). A wider application of these refrigerants in practice has not been possible so far because of various technical constraints. There is no practical experience with HFC-1234yf and other low-gwp candidate fluids in transport refrigeration. Although hydrocarbons are technically feasible and may even outperform HFC systems, flammability makes people concerned about their use. Where they do not exist, standards need to be developed to address the safety concerns. Carbon dioxide (R-744) is one of a few promising solutions in transport refrigeration. While direct emissions of R-744 are negligible, indirect emissions of R-744 may be comparable to HFCs depending on the climate where the vehicle is operated. Aboard marine vessels, because operation under high ambient temperatures is commonly required, R-774 use has been limited to low temperature stages of cascade or indirect system applications. Due to safety concerns, use of ammonia (R-717) has been limited to indirect and cascade systems on larger ships which do not carry passengers but professional crew only. HFC refrigerants will continue to be used on passenger vessels, and on small ships of all categories. Ammonia has not been used in road vehicle and container transport in vapour compression cycles. The transport industry is working to reduce the overall CO 2 emissions. The refrigerant type can influence both direct and indirect equivalent CO 2 emission of a vehicle. Refrigerant charge reduction, refrigerant leakage rate minimisation (for example use of hermetic/semi-hermetic compressors instead of open drive), and the use of low-gwp refrigerants influence the direct contribution. Design changes that would improve the energy efficiency can reduce the indirect contribution. Transition of power supply systems from traditional diesel engines to alternative propulsion systems (hybrid, electric, etc.) will influence refrigerantion system change and the choice of low-gwp refrigerants in the future. As in other refrigeration sectors, research and development of other not-in-kind systems, such as magnetic or acoustic refrigeration, remains in the laboratory prototype stage. Absorption and adsorption systems with water are under development too. Chapter 7: Air-to-air air conditioners and heat pumps On a global basis, air conditioners for cooling and heating (including air-to-air heat pumps) ranging in size from 2.0 kw to 420 kw comprise a significant segment of the air conditioning market (the majority are less than 35kW). Nearly all air conditioners and heat pumps manufactured prior to 2000 used HCFC-22 as their working fluid. The installed base of units in 2008 represented an estimated HCFC-22 bank exceeding one million metric-tonnes. Approximately 85% of the installed population uses HCFC-22. In 2008, HFC demand globally represented approximately 32% of the total refrigerant demand for these categories of products. Most Article 5 countries are continuing to utilise HCFC-22 as the predominant refrigerant in air conditioning applications. Options for new Equipment HFC refrigerant blends R-410A and R-407C are the dominant alternatives being used to replace HCFC-22 in air-conditioners. HC-290 is also being used to replace HCFC-22 in products having low refrigerant charges TOC Refrigeration, A/C and Heat Pumps Assessment Report 9

22 Air conditioners using R-410A and R-407C are widely available in most non-article 5 countries. Also, equipment using R-410A and R-407C is being manufactured in some Article 5 countries; especially in China where a large export market has created demand for these products. However, these units are typically not sold in the domestic market because of their higher cost. There are several low and medium GWP alternatives being considered as replacements for HCFC-22 and the high GWP HFCs (R-410A and R-407C). These refrigerants include lower GWP HFC refrigerants, HC-290 and R-744. HC-290 and some of the HFC refrigerants are flammable and will need to be applied in accordance with an appropriate safety standard such as IEC , which establishes maximum charge levels and ventilation requirements. A number of moderate and low GWP HFC refrigerants are being considered for use in air conditioners. These include HFC-32, HFC-152a, HFC-161, HFC-1234yf and blends of HFC-1234yf with other refrigerants: HFC-32 is a class A2L flammable HFC having a GWP of 675, which is approximately 30% that of R-410A. R-410A systems can be redesigned for HFC-32 with minor modifications. However, because of its A2L flammability rating it will need to be applied using a safety standard such as IEC HFC-152a is an A3 flammable low GWP HFC having thermodynamic characteristics similar to HFC-134a. While it has been evaluated as an alternative to HCFC-22, it is unlikely to be commercialised in unitary air conditioning applications because its low density and flammability result in significantly increased system costs. HFC-161 is a flammable low GWP refrigerant, which is being evaluated as a low GWP alternative to HCFC-22. Like all flammable refrigerants, it would need to be applied using appropriate safety standards. Pure HFC-1234yf is not likely to be used as a replacement for HCFC-22 in air conditioners because of its low volumetric capacity. However, HFC-1234yf can be blended with other non-odp refrigerants to arrive at thermodynamic properties similar to either HCFC-22 or R- 410A. Blends of this type are under development, but are not commercially available. Hydrocarbon refrigerants are also low GWP alternatives to HCFCs and HFCs for low charge applications. The most frequently used hydrocarbon refrigerant in air conditioning applications is HC The high flammability of HC-290 limits its use to lower charge applications. All flammable refrigerants need to be applied using an applicable safety standard such as IEC , which addresses the design requirements and charge limits for flammable refrigerants. Several manufacturers in China and India are now introducing low charge HC-290 split air conditioners. R-744, CO 2, offers a number of desirable properties as a refrigerant. However, R-744 has a low critical point temperature, which results in significant efficiency losses when it is applied at the typical indoor and outdoor air temperatures of air-to-air air conditioning applications; particularly in high ambient climates. However, a number of cycle enhancements and component additions can be made to improve the efficiency of R-744 systems. While the addition of efficiency enhancing components can improve the efficiency of R-744 systems, they also substantially increase the system cost. In order for R-744 systems to become commercially viable, cost effective mitigation of the efficiency issue will be required. High Ambient Considerations In the near term, regions with hot climates should be able to rely on the refrigerants and technologies that are currently commercially available to replace HCFC-22 (R-407C, R-410A and HC-290). However, when replacing HCFC-22 products with those using R-410A or R-407C the application engineer may need to take special consideration of the reduced capacity at the design ambient temperature when sizing the equipment for the design cooling load. When replacing HCFC-22 in low TOC Refrigeration, A/C and Heat Pumps Assessment Report

23 charge applications (small split, window and portable room air conditioners), the system designer may want to consider the use of HC-290. In the longer-term products using HFC-32, new low and medium GWP HFC blends and HC-290 are the preferable options for high ambient air conditioning applications. R-744 is not a preferred option for high ambient air conditioning applications because its very low critical temperature results in significant performance degradation during high ambient operation. Chapter 8: Water heating heat pumps Heat pumps are classified by heat source (air, water, or ground) and heat sink (air, water), resulting in designations such as air to water (air source, water sink) heat pumps. This chapter covers only systems where water is the sink. The products for industrial process heating are covered in chapter 5 Industrial systems. Air-to-air heat pumps are covered in chapter 7 (Air-to-air air conditioners and heat pumps). Heat pump water heaters are designed especially for heating service hot water (including domestic water) to a temperature between 55 and 90 ºC. Space heating heat pumps heat water for distribution to air handling units, radiators, or under-floor panels. The required water temperature depends on the type of emitter, low temperature application ranging from 25 to 35 C for under floor heating, for moderate temperature application such as air handling units around 45 C, for high temperature application such as radiant heating 55 to 60 C and for very high temperature application as high as 65 to 80 C such as for the fossil fuel boiler replacement market. The required warm water temperature affects the selection of the refrigerant. Heat pump systems are more efficient at lower sink temperatures, but each product must fulfil the required operating temperature. Air-to-water heat pumps have experienced significant growth in Japan, Europe, China, and Australia during the last five years. Efficient heat pumps can reduce global warming impact compared with fossil fuel burning systems significantly. The reduction depends on the efficiency level of the heat pump and the carbon emission per kwh of the electricity generation. The tendency of decarbonisation of electricity strengthens this positive effect year by year. Also the efficiency levels of the heat pumps are improving year by year. However, heat pumps tend to be higher in cost than fossil fuel systems because they employ complicated refrigerant circuits, larger heat exchangers and other special features. Government support programmes in Europe and Japan to promote heat pump systems have resulted in a rapid growth of heat pump system sales in recent years. More than 1 million air-to-water heat pumps were sold worldwide in Predictions of sales show very large growths in USA, Japan, China and Europe. Current refrigerant options for new heat pumps HFC-134a and HFC blends R-407C and R-410A are currently used for new water heating and space heating heat pumps to replace HCFC-22, R-407C with limited product redesign and R-410A for completely redesigned products. HC-290 has properties similar to those of HCFC-22 apart from flammability. Until 2004 almost half of the heat pumps sold in the EU used HC-290. Use in Europe has declined due to introduction of Pressure Equipment Directive. Development of R-744 heat pumps started around R-744 heat pump water heaters were introduced to the market in Japan in 2001, with heat pumps for heating of bath or sanitary water as the main application. The market for heat pump water heaters in Japan is steadily growing based on government and utility incentives TOC Refrigeration, A/C and Heat Pumps Assessment Report 11

24 Although the current market for space heating heat pumps for commercial buildings with combined radiator and air heating systems is limited, R-744 is considered to be a promising refrigerant. R-717 is a non-ods refrigerant and has a very low GWP, but it has higher toxicity and lower flammability characteristics. R-717 is used mainly for large capacity systems. Future Refrigerant Options for New heat pumps HFC-32 has a lower GWP of one third of R-410A. Heat pumps with HFC-32 can achieve lower charge than heat pumps with R-410A. HFC-32 has a low flammability with a low burning velocity. HFC-1234yf is similar in thermophysical properties to HFC-134a. For water heating and space heating heat pumps using HCFC-22, R-410A, R-407C, significant design changes would be required to optimise for HFC-1234yf. HFC-1234yf has low flammability with a low burning velocity. Due to the GWP value it has high potential in applications in systems that currently use HFC-134a. As sample supply of these refrigerants is very limited, it is too early to judge whether any of these chemicals will be commercialised and will show acceptable performance in heat pump systems. Future refrigerants options for new heat pumps include current options R-410A, HFC-134a, HC-290, HC 600a, R-744, and R-717 as well as HFC-32 and new refrigerants. Since the numbers of heat pumps covered by this chapter still are limited, the refrigerant bank is relatively small. Accordingly, the refrigerant emissions are low compared to other products. On the other hand, heat pumps will increase in quantity leading to higher net refrigerant requirements and emissions in the future. However, it is important to emphasise that there is a large potential to reduce CO2 emission generated by fossil fuel combustion systems by replacing them with heat pump systems. Chapter 9: Chillers Chillers predominantly are used for comfort air conditioning in commercial buildings and building complexes. They are coupled with chilled water distribution and air handling/air distribution systems. Chillers also are used for cooling in commercial and industrial facilities such as data processing and communications centers, electronics fabrication, and molding. Air-cooled chillers in capacities up to 1800 kw represent approximately 80 % of the annual unit production in chillers using positive displacement compressors (reciprocating piston, scroll, and screw). HFC-134a and R-410A are the most common refrigerants with the phase-out of HCFC-22. R- 407C has been used as a transition refrigerant. Some chillers are available with R-717 or hydrocarbon refrigerants primarily HC-290, HC-600a, or HC Such chillers are manufactured in small quantities compared to HFC-134a and R-410A chillers of similar capacities and require attention to flammability, and for R-717 also toxicity concerns, as reflected in safety codes and regulations. Chillers employing R-744 as the refrigerant are being marketed. For water-cooled chillers, both positive displacement compressors and centrifugal compressors are used. Positive displacement water-cooled chillers employ the same refrigerants as the air-cooled versions. Centrifugal chillers are dominant above 2 MW. Centrifugal chillers are provided with HCFC-123 or HFC-134a refrigerants though extremely limited use is made of HFC-245fa. HCFC-123 offers an efficient, very-low GWP option for centrifugal chillers. Under terms of the Montreal Protocol, use of HCFC-123 in new equipment will end in most developed countries by 2020 and by 2030 in Article 5 countries. Existing chillers employing CFC refrigerants are being replaced slowly by new chillers using HCFC- 123 or HFC-134a. Today s new chillers use 25-50% less electricity than the CFC chillers produced decades ago, so the savings in energy costs often justify replacement of ageing CFC chillers. R-717 is not suitable for use in centrifugal chillers as its use would require four or more stages or, in very large capacities, a switch to axial compressor designs. A continuing trend in chiller development is to improve both full-load and seasonal energy efficiency to address both energy-related global warming impacts and operating costs. A number of methods are TOC Refrigeration, A/C and Heat Pumps Assessment Report

25 used to achieve higher seasonal efficiencies. These include multistage compression with interstage economisers, use of multiple compressors to accommodate part-load conditions, continuous unloading capabilities for screw compressors, enhanced electronic controls, variable-speed compressor drives, and optimal sequencing of multiple chillers to maximise overall efficiency. Refrigerants suggested as alternatives to ODS or high-gwp refrigerants in chillers include R-717, hydrocarbons, R-744, R-718, HFC-32, and new low-gwp refrigerants such as HFC-1234yf. Chillers using R-718 as refrigerant carry a cost premium over conventional systems because of their larger physical size and the complexity of their compressor technology, often entailing axial compressor designs operating under high vacuum. HFC-1234yf and other low- or ultra-low GWP refrigerants are too new to allow assessment of their suitability for use in chillers at this time, though that is likely to change in subsequent assessments. Absorption chillers using working pairs ammonia-water (primarily in small capacities) or waterlithium bromide (generally in large capacities) are an alternative to chillers employing the vapourcompression cycle. They are particularly suitable for applications where surplus heat can be recovered. Other not-in-kind technologies in the research stage, such as thermoacoustic or magnetocaloric technologies, still are not ready for commercialisation and may not be found suitable or competitive. Of particular note for both ozone depletion and global climate change, chillers as a group incur very low release rates for refrigerants. The environmental impact of chillers is dominated by the energyrelated global warming associated with their energy consumption over their operating life (typically 20 years and sometimes longer than 40 years). Refrigerant emissions, with their direct global warming contributions, are a small fraction of the total global warming impact of chillers except for regions with very low carbon intensity for power generation. Chapter 10: Vehicle air conditioning Today all new passenger cars world-wide sold with air conditioning systems are using HFC-134a and the transition from CFC-12 is complete. About one fifth of the total global refrigerant emissions are from MACs (about 60 percent if only HFC refrigerant emissions are considered) including the emissions in production, use, servicing, and end-of-life. In the USA, 19% of the fleet of passenger vehicles is still using CFC-12 refrigerant based on recent survey results. The European Union has in place legislation for cars and light trucks banning the use of refrigerants with GWP>150 [e.g.; HFC- 134a] in new-type vehicles from 2011 and all new vehicles from There are limited replacement refrigerants with a global warming potential (GWP) less than 150. Other countries will probably follow the regulatory direction of the EU or provide incentives to reduce the usage of HFC-134a in vehicles. For MAC systems, the use of hydrocarbons or blends of hydrocarbons as a refrigerant has been investigated but has so far not received support from vehicle manufacturers as a possible alternative technology due to safety concerns. In Australia and the North America, hydrocarbon refrigerants have been introduced as drop-in refrigerants to replace CFC-12 (which is illegal in the USA and in some Australian states). These same refrigerants are used to a lesser extent for a replacement of HFC-134a. Up to now, car manufacturers and suppliers have evaluated three refrigerant options for new car and truck air conditioning systems, R-744, HFC-152a and HFC-1234yf. All three have GWPs below the EU threshold of 150 and can achieve fuel efficiency comparable to existing HFC-134a systems. The CO2 equivalent impact of direct emissions from the refrigerant over the vehicle lifetime is much less than the impact related to the energy required to operate the system. The energy required to operate the MACs results in increased CO2 vehicle tail pipe emissions. Therefore, MAC systems designed to provide efficient cooling performance have become the major environmental goal. With the usage of appropriate controls and components, all three refrigerant options have been demonstrated to be comparable to HFC-134a with respect to cooling performance and total CO2 equivalents of MAC systems TOC Refrigeration, A/C and Heat Pumps Assessment Report 13

26 Hence, the global warming impact is almost identical for all three refrigerant options when considered on a global basis. Adoption of any of the refrigerant choices would therefore be of similar environmental benefit. The decision of which refrigerant to choose will have to be made based on other considerations, such as regulatory approval, cost, system reliability, safety, heat pump capability, suitability for hybrid electric vehicles, and servicing. The emerging global car manufacturers refrigerant choice for future car air conditioning systems seems to be HFC-1234yf and one manufacturer has announced the intention to introduce this refrigerant in car serial production in Currently, hurdles exist (miscibility with oil, stability problems in the presence of small amounts of water and air in the air conditioning system, mixing with HFC-134a, additional costs) that will require resolution prior to the commercial implementation of HFC-1234yf as refrigerant for car air conditioning. OEM s indicate that they will design HFC-1234yf MAC systems in such a way that these systems can safely be used with the refrigerant HFC-134a as well. This will affect the world-wide transition from HFC-134a to HFC-1234yf for MAC systems. The development status of other refrigeration technologies, like sorption or thermoelectric systems, are still far away from serial production and presently show very poor price competitiveness and poor system performance and efficiency. The rapid evolution of hybrid electric vehicles and electric vehicles with electrically driven compressors introduces new challenges for any new alternative refrigerant. At present, no regulation exists that controls the use of fluorinated greenhouse gases as refrigerants for MAC systems in buses and trains. It is likely that the choice of refrigerant of passenger car air conditioning systems will influence the choice of refrigerant for air conditioning systems in buses and trains. World-wide, an approximate 50% of the bus and train fleet is still equipped with HCFC-22 systems. The rest use mostly HFC-134a or R-407C systems. Most new bus or train air conditioning systems are equipped with the refrigerants HFC-134a or R-407C. The only reported low GWP refrigerant activities are on-going fleet tests of R-744 systems in buses TOC Refrigeration, A/C and Heat Pumps Assessment Report

27 Chapter 1 Introduction Chapter Lead Authors Lambert Kuijpers Roberto de A. Peixoto 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 15

28 1 Introduction 1.1 Montreal Protocol Developments In 1981, the United Nations Environment Programme (UNEP) began negotiations to develop multilateral protection of the stratospheric ozone layer. These negotiations resulted in the Vienna Convention for the Protection of the Ozone Layer, adopted in March In September 1987, 24 nations, amongst which the United States, Japan, the Soviet Union, a large number of Western European countries, Egypt, Ghana, Kenya, Mexico, Panama, Senegal, Togo and Venezuela, as well as the European Community as a regional organisation, signed the Montreal Protocol on Substances that Deplete the Ozone Layer. The Montreal Protocol entered into force on January 1, This international environmental agreement originally limited production of specified CFCs to 50 percent of the 1986 levels by the year 1998 and called for a freeze in production of specified halons at 1986 levels starting in By April 1991, 68 nations had already ratified the Protocol: these represented over 90 percent of the 1991 world production of CFCs and halons. At present all countries in the world have ratified the Vienna Convention and the Montreal Protocol, so its Decisions are truly global. Shortly after the 1987 Protocol was negotiated, new scientific evidence conclusively linked CFCs to the depletion of the ozone layer and indicated that depletion had already occurred. Consequently, many countries called for further actions to protect the ozone layer by expanding and strengthening the original control provisions of the Montreal Protocol, and they decided that an assessment should be carried out in the year In June 1990, the Parties to the Montreal Protocol met in London, considered the data from the 1989 Assessment Reports, and agreed to Protocol adjustments requiring more stringent controls on the CFCs and halons as specified in the original agreement. They also agreed to amendments placing controls on other ozone depleting substances, including carbon tetrachloride and 1,1,1-trichloroethane. In London, a new assessment was again decided, which was carried out in 1991 for consideration in The London Amendment acknowledged the need for financial and technical assistance of the developing countries, and established a (Interim) Multilateral Fund. At their 4th Meeting in Copenhagen, Denmark, the Parties considered the Assessment Reports and took decisions that again advanced the phase-out schedules in non-article 5 countries for most ozone depleting substances, including methyl bromide. They continued the financial mechanism and decided a new assessment to be carried out in 1994 (Decision IV/13), for decisions by the Parties at their 1995 Meeting. At the 7th Meeting in Vienna (November 1995) the Parties considered the Assessment Reports and focused on the progress made in phasing out ozone depleting chemicals. A reduction in the maximum permissible annual consumption of HCFCs (the cap ) for the developed countries was decided (2.8% instead of 3.1%, as decided in Copenhagen). A control schedule for the HCFC consumption for the Article 5 countries was agreed upon (in fact, this consisted of a freeze in consumption by the year 2016 and a phase-out by the year 2040). Article 5 countries also agreed to freeze their methyl bromide consumption by the year The Parties, in Decision VII/34, requested a new assessment to be carried out by the Assessment Panels in the year Updated and more detailed Terms of Reference for the Technology and Economic Assessment Panel and its Technical Options Committees (compared to the original 1989 ones) were decided and were given in the 1996 Report of the Technology and Economic Assessment Panel (these TOR were again considered in the light of disclosure of interest and conflict of interest at the 18th Meeting of the Parties (2006) in New Delhi, where a separate Decision on these topics was taken). The 15th Meeting of the Parties, held in Nairobi in November 2003, considered the 2002 Assessment Reports, next to a number of other issues, including destruction technologies, process agent uses and TOC Refrigeration, A/C and Heat Pumps Assessment Report

29 the handling and destruction of foams at end-of-life. Parties decided to request the Assessment Panels to update their 2002 reports in 2006 and submit them to the Secretariat by 31 December 2006 for consideration by the Open-ended Working Group and by the Nineteenth Meeting of the Parties in 2007 (MOP-19, to be held in Montreal, September 2007). In the relevant Decision (XV/53), the Parties also requested the TEAP to consider, among other matters, five specific issues, including "(c) Technically and economically feasible choices for the elimination of ozone-depleting substances by the use of alternatives that have superior environmental performance with regard to climate change, human health and sustainability;" and "(e) Accounting of the production and use of ozone-depleting substances and of ozone-depleting substances in inventory or contained in products". The 19th Meeting of the Parties, held in Montreal in September 2007 (on the occasion of the twentieth Anniversary of the Protocol) reached agreement to adjust the Montreal Protocol's HCFC phase-out schedule to accelerate the phase-out of production and consumption of HCFCs. This decision will result in significant reduction of ozone depletion and well as of global warming or global climate forcing. This meeting also considered all 2006 Assessment Reports, next to a large number of other issues. Parties decided to request the Assessment Panels to update their 2006 reports in 2010 and submit them to the Secretariat by 31 December 2010 for consideration by the Open-ended Working Group and by the Twenty-Third Meeting of the Parties in 2011 (MOP-23). In the relevant Decision (XIX/20), the Parties also requested the TEAP (and its TOCs) in paragraph 6 to consider (a) The impact of the phase-out of ozone-depleting substances on sustainable development, particularly in Parties operating under paragraph 1 of Article 5 and countries with economies in transition; (b) Technical progress in all sectors; (c) Technically and economically feasible choices for the reduction and elimination of ozonedepleting substances through the use of alternatives, taking into account their impact on climate change and overall environmental performance; (d) Technical progress on the recovery, reuse and destruction of ozone-depleting substances; (e) Accounting for: the production and use in various applications of ozone-depleting substances; ozone-depleting substances in inventories; ozone depleting substances in products; and the production and use in various applications of very short-lived substances; (f) Accounting of emissions of all relevant ozone-depleting substances with a view to updating continuously use patterns and co-ordinating such data with the Scientific Assessment Panel in order periodically to reconcile estimated emissions and atmospheric concentrations. Together with the Science and Environmental Effects Assessment reports, the 2010 TEAP Assessment Report -together with the 2010 TOC Assessment Reports- forms the direct response to the abovementioned decision. In the important Decision XIX/6 on the HCFC phase-out for developing countries, taken at MOP-19 in Montreal in September 2007, subparagraphs mention: To encourage Parties to promote the selection of alternatives to HCFCs that minimize environmental impacts, in particular impacts on climate, as well as meeting other health, safety and economic considerations; To agree that the Executive Committee, when developing and applying funding criteria for projects and programmes, and taking into account para 6, give priority to cost-effective projects and programmes which focus on, inter alia: 1. Phasing-out first those HCFCs with higher ozone-depleting potential, taking into account national circumstances; 2. Substitutes and alternatives that minimize other impacts on the environment, including on the climate, taking into account global-warming potential, energy use and other relevant factors; etc TOC Refrigeration, A/C and Heat Pumps Assessment Report 17

30 In Decision XX/8 on substitutes for HCFCs and HFCs, taken at MOP-20 in Doha, it is mentioned that more information on the HCFC and HFC substitution process is needed: Recognizing that decision XIX/6 encourages Parties to promote the selection of alternatives to hydrochlorofluorocarbons to minimize environmental impacts, in particular impacts on climate, Recognizing also that there is scope for coordination between the Montreal Protocol and the United Nations Framework Convention on Climate Change and its Kyoto Protocol for reducing emissions and minimizing environmental impacts from hydrofluorocarbons, and that Montreal Protocol Parties and associated bodies have considerable expertise in these areas which they could share, Recognizing further that there is a need for more information on the environmental implications of possible transitions from ozone-depleting substances to high-global warming potential chemicals, in particular hydrofluorocarbons, 1. To request the Technology and Economic Assessment Panel to update the data contained within the Panel s 2005 Supplement to the IPCC/TEAP Special Report 1 and to report on the status of alternatives to hydrochlorofluorocarbons and hydrofluorocarbons, including a description of the various use patterns, costs, and potential market penetration of alternatives no later than 15 May 2009; 2. To request the Ozone Secretariat to prepare a report that compiles current control measures, limits and information reporting requirements for compounds that are alternatives to ozonedepleting substances and that are addressed under international agreements relevant to climate change; etc. In Decision XXI/9 on substitutes for HCFCs and HFCs, taken at MOP-21 at Port Ghalib in Egypt, it is again mentioned that more information on the HCFC and HFC substitution process is needed: Recalling that decision XIX/6 requests the Parties to accelerate the phase-out of production and consumption of hydrochlorofluorocarbons (HCFCs); Mindful of the need to safeguard the climate change benefits associated with phase-out of HCFCs; Aware of the increasing availability of low-global Warming Potential (GWP) alternatives to HCFCs, in particular in the refrigeration, air-conditioning and foam sectors; Aware also of the need to appropriately ensure the safe implementation and use of low-gwp technologies and products; Recalling para 9 and 11 (b) of decision XIX/6; 1. To request the Technology and Economic Assessment Panel (TEAP), in its May 2010 Progress Report and subsequently in its 2010 full assessment, to provide the latest technical and economic assessment of available and emerging alternatives and substitutes to HCFCs; and the Scientific Assessment Panel (SAP) in its 2010 assessment to assess, using a comprehensive methodology, the impact of alternatives to HCFCs on the environment, including on the climate; and both the SAP and the TEAP to integrate the findings in their assessments into a synthesis report; 2. To request the Technology and Economic Assessment Panel in its 2010 progress report: (a) To list all sub-sectors using HCFCs, with concrete examples of technologies where low- GWP alternatives are used, indicating what substances are used, conditions of application, their costs, relative energy efficiency of the applications and, to the extent possible, available markets and percentage share in those markets and collecting concrete information from various sources including information voluntarily provided by Parties and industries. To further ask TEAP to compare these alternatives with other existing technologies, in particular, high-gwp technologies that are in use in the same sectors; TOC Refrigeration, A/C and Heat Pumps Assessment Report

31 (b) To identify and characterize the implemented measures for ensuring safe application of low-gwp alternative technologies and products as well as barriers to their phase-in, in the different sub-sectors, collecting concrete information from various sources including information voluntarily provided by Parties and industries; (c) To provide a categorization and reorganization of the information previously provided in accordance with decision XX/8 as appropriate, updated to the extent practical, to inform the Parties of the uses for which low- or no-gwp and/or other suitable technologies are or will soon be commercialized, including to the extent possible the predicted amount of high-gwp alternatives to ozone-depleting substances uses that can potentially be replaced; 3. To request the Ozone Secretariat to provide the UNFCCC Secretariat with the report of the workshop on high global-warming-potential alternatives for ozone-depleting substances; 4. To encourage Parties to promote policies and measures aimed at avoiding the selection of high- GWP alternatives to HCFCs and other ozone-depleting substances in those applications where other market-available, proven and sustainable alternatives exist that minimise impacts on the environment, including on climate, as well as meeting other health, safety and economic considerations in accordance with decision XIX/6; 5. To encourage Parties to promote the further development and availability of low-gwp alternatives to HCFCs and other ozone-depleting substances that minimise environmental impacts particularly for those specific applications where such alternatives are not presently available and applicable; 6. To request the Executive Committee as a matter of urgency to expedite the finalisation of its guidelines on HCFCs in accordance with Decision XIX/6; 7. To request the Executive Committee, when developing and applying funding criteria for projects and programmes regarding in particular the phase-out of HCFCs: (a) to take into consideration paragraph 11 of decision XIX/6; (b) to consider providing additional funding and/or incentives for additional climate benefits where appropriate; (c) to take into account, when considering the cost-effectiveness of projects and programmes, the need for climate benefits; and (d) to consider in accordance with decision XIX/6, further demonstrating the effectiveness of low-gwp alternatives to HCFCs, including in Air Conditioning and refrigeration sectors in high ambient temperature areas in Article 5 countries and to consider demonstration and pilot projects in Air conditioning and refrigeration sectors which apply environmentally sound alternatives to HCFCs; 8. To encourage Parties to consider reviewing and amending as appropriate, policies and standards which constitute barriers to or limit the use and application of products with low- or zero-gwp alternatives to ozone-depleting substances, particularly when phasing out HCFCs. The decisions as given above are based upon the perception that more actions are needed for the protection of the ozone layer, however, the emphasis in all relevant paragraphs is on the climate aspect of high-gwp ozone depleting substances, the high or possibly low-gwp replacements and their climate impact. In particular the above Decision XXI/9 mentions numerous times the development, availability, implementation and use of low-gwp alternatives to HCFCs, as well as a comparison with high-gwp alternatives. How the RTOC has been involved in the work of the Task Forces that addressed the requests by Parties in Decisions XX/8 and XXI/9 is given in section TOC Refrigeration, A/C and Heat Pumps Assessment Report 19

32 1.2 The UNEP Technology and Economic Assessment Panel Four Assessment Panels were defined in the original Montreal Protocol as signed 1987, i.e. Assessment Panels on (1) Science, and on (2) Environmental Effects, (3) a Technical Assessment and (4) an Economics Assessment Panel. The Panels were established in ; their Terms of Reference can be found in the Meeting Report of the 1st Meeting of the Parties, held in Helsinki in Under the Technical Assessment Panel five Subsidiary Bodies, the so called Technical Options Committees were defined (see Meeting Report of the First Meeting of the Parties in Helsinki). The Technical and Economics Assessment Panels were merged after the Meeting in London in 1990 to the Technology and Economic Assessment Panel. At the Meeting in Copenhagen, it was decided that each Assessment Panel should have up to three co-chairs, with at least one from an Article 5 country. After the discussions on methyl bromide held at the meeting in Copenhagen, the Methyl Bromide Technical Options Committee was founded at The Hague in early From 1993 until 2001, the UNEP Technology and Economic Assessment Panel (TEAP) had 7 standing Technical Options Committees (TOCs). In 2001, the Economics Options Committee was disbanded, which resulted in a number of 6 Committees. In 2005, the Aerosols TOC and the Solvents TOC were disbanded, and a new Medical TOC and Chemicals TOC were formed by merging certain parts of the Aerosols and the Solvents TOC, and replenishing the membership with additional, new experts. Currently there are the following TOCs: 1. Chemicals Technical Options Committee 2. Flexible and Rigid Foams Technical Options Committee 3. Halons Technical Options Committee 4. Medical Technical Options Committee 5. Methyl Bromide Technical Options Committee 6. Refrigeration, A/C and Heat Pumps Technical Options Committee Where, originally, the Panels were considered as the bodies that should carry out assessments pursuant to Article 6 under the Montreal Protocol (at least every four years), it is particularly the TEAP that has become a standing advisory group to the Parties on a large number of Protocol issues. The evolving role of the TEAP -and its Technical Options Committees and other temporary Subsidiary Bodies- can be explained by the fact that the focus of the Montreal Protocol has shifted from introducing and strengthening control schedules (based upon assessment reports) to the control of the use of controlled chemicals and to compliance with the Protocol. This implies the study of equipment, of use patterns, of trade, imports and exports etc. The Parties in Copenhagen took a number of decisions, which concern the work of the Technology and Economic Assessment Panel and its Committees. A decision (IV/13) on "Progress" requested the TEAP and its TOCs to annually report on progress in the development of technology and chemical substitutes. This decision was re-evaluated and restated in the meeting in Vienna, in 1995 (VII/34). As a result, progress reports have been conceived annually by the TEAP and its Committees; they were submitted to the Parties in the years as part of the annual report of the TEAP (next to the progress reports, the annual reports deal with a large variety of issues on the basis of which Parties have taken certain decisions in the period). In Vienna, the Parties also requested to offer the assistance of the Scientific, Environmental Effects and Technology and Economic Assessment Panels to the SBSTA, the Subsidiary Body on Science and Technology under the United Nations Framework Convention on Climate Change (UNFCCC), as necessary (VII/34). The SBSTA encouraged the Secretariat to continue its close collaboration with other relevant bodies such as the Technology and Economic Assessment Panel of the Montreal Protocol on Substances that Deplete the Ozone Layer, on technical and methodological issues. In order to assess the status of the use of fluorochemicals, the IPCC and the TEAP organised a workshop in Petten, the Netherlands, in mid Output from this workshop was reported to the SBSTA in October 1999, before the UNFCCC Fifth Conference of the Parties (COP-5). Output was also used in the drafting of a TEAP report on HFCs and PFCs, which became available in October A new TOC Refrigeration, A/C and Heat Pumps Assessment Report

33 decision on a study on the status of HFCs and alternatives to HFCs and PFCs, to be performed in , was decided by the Parties to the UNFCCC in Delhi (COP-8) in 2002 and by the Parties to the Montreal Protocol in 2002 (MOP-14, Rome, Mirror Decision XIV/10). It asked for a joint undertaking by the Intergovernmental Panel on Climate Change (IPCC) and TEAP in order to prepare a Special Report on Safeguarding the climate system and protecting the ozone layer; issues related to hydrofluorocarbons and perfluorocarbons. A Steering Committee, consisting of six members (three IPCC Working Group co-chairs and the three TEAP co-chairs) has directed the Special Report study. The report (as well as a Technical Summary and a Summary for Policy Makers) has been adopted by governments in a Meeting in Addis Ababa, April 2005, and was published mid This Report has been the basis for many discussions that took place at the various Meetings of the Parties to the Montreal Protocol and the Kyoto Protocol. A Supplement Report to the Special Report was published in 2006 and contained a large amount of information on the size of banks and emissions in the different sectors, where refrigeration and air conditioning is actually the most important contributing sector. At the MOP-19 in Montreal an important Decision, Decision XIX/6 (as described in section 1.1), was taken on the accelerated phase-out of HCFCs in Article 5 countries. In the decision, a reduction schedule for production and consumption was defined for the period , with a freeze in 2013 and a servicing tail until As a first consequence of Decision XIX/6, the Parties requested the TEAP and its RTOC in Decision XIX/8, to report on the status of substitutes and alternatives to HCFCs under high ambient conditions. The report was done by a Subcommittee of the RTOC, and submitted to Parties in a preliminary form in 2009 and in its final form in In 2008, Parties requested the TEAP and its committees, in Decision XX/8 (see above), to look at the status of alternatives in the different sectors and subsectors, as covered by the six Technical Options Committees. In a report by a Task Force, a large amount of material was summarised; this report also contained updated information on banks and emissions from all sectors, including refrigeration, AC and heat pumps as well as foams. In 2009, in Decision XXI/9 (see above), on HCFCs and environmentally sound alternatives, Parties requested the TEAP to update the information from the XX/8 report, and to report on the status of low GWP alternatives for the replacement of HCFCs, and to report on the comparison of performances of high and low GWP alternatives. TEAP established again a Task Force -having a large number of RTOC members-, which reported on the definition of the term low-gwp and high-gwp, and particularly on the 2009/2010 status of (low GWP) substitutes and alternatives to HCFCs in all sectors and subsectors. The information collected for this XXI/9 report has also been used in the preparation of the 2010 TOC Assessment Reports, including that of the RTOC. The 2010 Technical and Economic Assessment study has been carried out by the Technology and Economic Assessment Panel and its six Technical Options Committees. The six Committees consisted of more than 140 experts from a large number of countries (for a list, see the annex to the Technology and Economic Assessment Panel Report 2010). The 2010 Technical Options Committees consisted of several members of the 1998, 2002, and 2006 Committees and additional new experts, to provide the widest possible international participation in the review. Much attention was again paid to adequate participation by technical experts from Article 5 and CEIT countries, dependent upon budgetary constraints. The Technical Options Committee reports have been subject to a peer review before final release. The final version of the reports will be distributed internationally by UNEP and will also be available on the Internet ( TOC Refrigeration, A/C and Heat Pumps Assessment Report 21

34 1.3 The Technical Options Committee Refrigeration, A/C and Heat Pumps This Technical Options Committee Assessment Report on Refrigeration, A/C and Heat Pumps (hereafter called RTOC Assessment Report ) also forms part of the UNEP review pursuant to Article 6 of the Montreal Protocol. It is part of the 2010 assessment work of the Technology and Economic Assessment Panel (requested by the Parties in Montreal (XIX/20)). The information collected (particularly in the form of the the Executive Summaries) will also be part of the Technology and Economic Assessment Report 2010, as well as the overall 2010 Synthesis Report composed by the three Assessment Panel co-chairs, the beginning of The 2010 RTOC Assessment Report has been drafted in the form of a number of chapters. There are chapters on refrigerants and their properties, on the different R/AC application areas and one chapter on refrigerant conservation. The structure of the 2010 report was chosen similar to the structure of the 2006 RTOC Assessment Report. Table 1-1: "Member countries" of UNEP's Refrigeration, A/C and Heat Pumps Technical Options Committee Austria Belgium Brazil China Czech Republic Denmark France Georgia Germany India Jamaica Japan Netherlands Norway Sweden United Kingdom United States Each of the chapters was developed by 2-6 experts in the specific sector, and each chapter was chaired by a Chapter Lead Author - who did the larger part of the drafting and the co-ordination. The 2010 RTOC included 29 representatives from Asian, European, Latin and North American companies, universities and governments, as well as independent experts (see Table 1-1). These representatives have been full (reporting) members; as resource persons the RTOC also had a small number of reviewing members (actually, only in a few chapters, e.g. chapters 2 and 9). Affiliations of the members are listed in Table 1-2 (29 organisations (including consultancies) were involved in the drafting of the report). The names and contact details of all members are given as an appendix to this RTOC Assessment Report. Several drafts of the report were made, reviewed by the separate chapters and discussed in five RTOC meetings (outline September 2008, preliminary draft March 2009, draft September 2009, peer review draft August 2010 and final report December 2010). A preliminary committee meeting was held in Copenhagen (back to back with an IIR meeting), September Drafting and reviewing meetings were held in Canada (Montreal), March 2009, Brazil (Sao Paulo), September 2009, Czech Republic (Prague), August 2010, and China (Hangzhou), December The report has been peer reviewed by a number of institutions and associations, each of them reviewing the different chapters sections in a co-ordinated effort in a tight timeframe, i.e., between the end of October and the end of November 2010 (see Table 1-3 for the peer review organisations involved). Peer review comments were collected and sorted out, and subsequently sent to all CLAs. They studied all peer review comments and made suggestions how to deal with the comments before the RTOC Meeting in December TOC Refrigeration, A/C and Heat Pumps Assessment Report

35 Table 1-2: Affiliations of the members of UNEP's Technical Options Committee on Refrigeration, A/C and Heat Pumps Braunschweig University Calm, James M., Engineering Consultant Carrier Corporation Daikin Europe Danish Technological Institute Devotta, Sukumar, Independent Consultant Paris Mines Tech, Ecole des Mines FK Consultancy General Electric, Consumer Industrial, Retired heat AG / UHTC Hill (Consultant) IEA Heat Pump Center Indian Institute of Technology Delhi Ingersoll Rand Johnson Controls Johnson Controls Karlsruhe University of Applied Sciences Maua Institute of Technology National Refrigeration Association, representative Nelson, private person Panasonic Corporation Re/genT b.v. Re-phridge Consultancy SINTEF Energy Research, Trondheim Star Refrigeration Technical University Eindhoven The Trane Company U.S. Environmental Protection Agency HAPI Consultancy, Joinville Zhejiang University, Hangzhou Germany U.S.A. U.S.A. Belgium Denmark India France U.S.A. U.S.A. Austria/Germany U.S.A. Sweden India Czech Republic Denmark USA Germany Brazil Georgia Jamaica Japan Netherlands United Kingdom Norway United Kingdom Netherlands U.S.A. U.S.A Brazil China The RTOC worked in chapter groups to address all peer review comments during the RTOC meeting in Hangzhou, China, December CLAs took note of how the groups decided to deal with the comments and whether or not to modify or amend the text; all suggestions were archived per chapter. CLAs then submitted the final chapters to the co-chairs. The final report was put together including Key Messages and an Abstract Executive Summary upfront, as well as Executive Summaries for all chapters (except chapter 11). UNEP s Ozone Secretariat assisted in final formatting and heading style insertions. The report was then once more circulated to all RTOC members for a final check. The RTOC greatly acknowledges the voluntary involvement from the peer reviewers and the peer review institutions TOC Refrigeration, A/C and Heat Pumps Assessment Report 23

36 Table 1-3: Institutions and organisations involved in the peer review of the 2010 RTOC report ACEA AHRI AIRAH ARAP CRAA CRT DKV EIA EHPA EPEE Greenpeace IIAR IIR IOR JAMA JRAIA SAE SAIRAC Shecco Transfrigoroute Transicold European Automobile Manufacturers' Association American Heating and Refrigeration Institute Australian Institute of Refrigeration, Air conditioning and Heating Alliance for Responsible Atmospheric Policy Chinese Refrigeration and Air Conditioning Association CRT Cambridge German Refrigeration Association Environmental Investigation Agency European Heat Pump Association European Partnership for Energy and Environment Greenpeace International International Institute for Ammonia Refrigeration International Institute for Refrigeration Institute of Refrigeration UK Japanese Automotive Manufacturer Association Japanese Refrigeration and Air Conditioning Industry Association Society of Automotive Engineers South African Institute for Refrigeration and Air Conditioning Shecco Brussels Transfrigoroute International Carrier Transicold 1.4 Refrigeration, Air Conditioning and Heat Pumps General Remarks Refrigeration, air conditioning and heat pump applications represent more than 70% of the ODS and replacement substances used; it is also one of the most important energy using sectors in the present day society. Estimates are difficult to give but as an average for the developed countries, its share in electricity use is thought to vary between 10 and 30%. The economic impact of refrigeration technology is much more significant than generally believed; 300 million tonnes of goods are continuously refrigerated. While the yearly consumption of electricity may be huge, and where the investment in machinery and equipment may approach US$100,000 million, the value of the products treated by refrigeration either alone will be four times this amount. This is one of the reasons that economic impacts of the phase-out of refrigerant chemicals (such as CFCs in the past, and HCFCs in Article 5 countries in the foreseeable future) have been and still are difficult to estimate. Refrigeration and air conditioning applications vary enormously in size and temperature level. A domestic refrigerator has an electrical input between W and contains less than g of refrigerant (dependent on the type of refrigerant), whereas industrial refrigeration and cold storage is characterised by temperatures between -10 C and -40 C, with electrical inputs up to several MW and refrigerant contents of many hundred kilograms. Air conditioning and heat pumps may show evaporation temperatures between 0 C and +10 C, significantly different from refrigeration applications, and vary enormously in size and input. In principle one can therefore discriminate between four main areas which each have subsectors: (i) the food chain in all its aspects, from cold storage via transport to domestic refrigeration, (ii) process air conditioning and refrigeration, (iii) comfort air conditioning, from air cooled equipment to water chillers, including heat pumps, and (iv) mobile air conditioning, with very specific, different aspects TOC Refrigeration, A/C and Heat Pumps Assessment Report

37 This is one of the reasons that all the equipment is considered in this report in a large number of separate chapters or sections. Options and aspects for the refrigeration vapour compression cycle deserve most attention, since it is unlikely that during the next years other principles will take over a substantial part of the market. In all application sectors described in the separate chapters in this report, most of the attention is focused on the vapour compression cycle. As stated, this cycle has so far provided a simple, economic, efficient and reliable way for refrigeration (this includes cycles using ammonia, carbon dioxide, fluorochemicals and hydrocarbons as refrigerants). The process of selecting a refrigerant for the vapour compression cycle is rather complex (not taking into account economic and costs aspects), since a large number of parameters need to be investigated concerning their suitability for certain designs, including: - thermodynamic and transport properties; - temperature ranges; - pressure ratios; - compressor requirements; - material and oil compatibility; - health, safety and flammability aspects; - environmental parameters such as ODP, GWP and atmospheric lifetime. These selection criteria were elaborated upon in various chapters of various UNEP RTOC Assessment Reports, and these selection criteria have not changed during the last years. Since then, it is the emphasis on the emissions of greenhouse gases that has increased; this can be directly translated to thermodynamic efficiency and quality of the equipment (leakage of refrigerant). The future of mankind, and his food supply in particular, depends on the availability of sufficient energy and on the availability of efficient refrigeration methods. Of course, this aspect must be more than balanced by a concern for the conservation of the biosphere, including in particular the global warming effect. Energy efficiency, therefore, is one of the most important aspects Long Term Options and Energy Efficiency CFC production has been phased out since fifteen years in the developed countries, and the CFC phase-out in the developing countries has been completed by Where HCFCs have been largely phased out in the developed countries, the phase-out in the Article 5 countries is now asking full attention. In both developed and developing countries, HFCs have so far been important substitutes for CFCs and HCFCs. In many applications, alternatives to HCFCs have become commercially available, as pure HFCs, as blends of HFCs or as non-hfc alternatives. Therefore, HFCs have gained a large share of the replacement market. In particular the necessary incentives remain to be provided to Article 5 countries to transition from HCFCs to non-hcfc refrigerants, which will include both HFCs and non-fluorocarbon alternatives. It should be noted, however, that the changing refrigerant options are only part of the driving force for innovations in refrigeration and A/C equipment. Innovation is an ongoing independent process, which has to take into account all the environmental issues involved. In the long term, the role of non-vapour compression methods such as absorption, adsorption, Stirling and air cycles etc. may become more important; however, vapour compression cycles are thought to remain the most important candidates TOC Refrigeration, A/C and Heat Pumps Assessment Report 25

38 For the long term, there remain, in fact, only five important different refrigerant options for the vapour compression cycle in all refrigeration and A/C sectors, listed alphabetically: ammonia (R-717); carbon dioxide (R-744); hydrocarbons and blends (HCs, e.g. HC-290, HC-600a, HC-1270 etc.); hydrofluorocarbons (HFCs, unsaturated HFCs (HFOs)); water (R-718). None of the above mentioned refrigerants is perfect; all have both advantages and disadvantages that should be considered by governments, equipment manufacturers and equipment users. For instance, ammonia, carbon dioxide and hydrocarbons have negligible or low Global Warming Potentials (GWP), most HFCs have a relatively high GWP (this is not valid for the unsaturated HFCs (HFOs), which have a low GWP), ammonia is more toxic than the other options, and ammonia and hydrocarbons are flammable to certain extents. Appropriate equipment design, maintenance and use can address these concerns, though sometimes at the cost of greater capital investment or lower energy efficiency. The five refrigerant options above are in different stages of development or commercialisation. High GWP HFCs are widely applied in many sectors, ammonia and hydrocarbons enjoy growth in sectors where they can be easily accommodated, and for certain applications, CO 2 equipment is being further developed and a large number of CO 2 installations have been extensively tested on the market. Currently CO 2 is gaining a substantial part of the supermarket refrigeration equipment market in certain regions. Water is used and may see some increase in use in limited applications. Work is being done by several committees in developing standards to permit the application of new refrigerants, and it is the intent of companies to reach world-wide accepted limits in those different standards. Similarly, energy efficiency research is partly spurred by the role of energy production in carbon dioxide emissions. Options for energy efficient operation of equipment form an important issue in each of the chapters of this 2010 RTOC Assessment report. The Framework Convention on Climate Change via its Kyoto Protocol as adopted in 1997 considers six important global warming gases in one basket (CO 2, CH 4, N 2 O, and the industrial gases HFCs, PFCs and SF 6 ) using their respective Global Warming Potentials (GWP). The control process is based upon the control of equivalent global warming emissions via reductions. Of course, under the Kyoto Protocol, any national government is free to prioritise emission reductions, which in principle could also be done via a phase-out of HFC chemicals at a certain stage. On the contrary, it could also involve a certain growth in certain sectors in certain countries (e.g., the HFCs) which would have to be balanced by larger than average reductions in other greenhouse gas emissions. Although CFC and HCFC are not in the basket of Kyoto protocol, these are also significant warming impact gases. HFCs have similar GWP values than HCFCs but the GWPs of the CFCs are much higher. Insofar, the Montreal Protocol has been quite effective in reducing warming impacts during the CFC phase-out period. In the Special Report (IPCC TEAP, 2005) and its Supplement Report, as mentioned before, two scenarios were developed for the projections of the demand, banks and emissions of CFCs, HCFCs, HFCs and some PFCs (where these are used as replacements for ozone-depleting substances). Annually, the demand is defined as the amount of chemical required for use in a certain year, banks are equal to the different inventories of products, and the emissions are defined as the amount of chemical that is emitted during manufacturing, plus the amount emitted during the lifetime of the product (leakage from banks), plus the amount of chemical emitted at disposal. The activities underlying emissions of fluorocarbons are expected to expand significantly. These activities (such as the requirements for refrigeration, air conditioning and insulation) will involve a number of technologies. In non-article 5 countries, the use and emissions of CFCs and HCFCs will decline and TOC Refrigeration, A/C and Heat Pumps Assessment Report

39 stop as all obsolete equipment is retired. In Article 5 countries, ozone-depleting substances (particularly HCFCs) may be used for another one to two decades; a virtual phase-out has been decided for 2030 (Decision XIX/6). Current emission profiles are largely determined by historic use patterns, resulting in a still relatively high contribution (at present) from CFCs and HCFCs banked in equipment and foams. The largest bank of ODS (CFCs) is in foam products, which are located in the non-article 5 countries. This will remain the case for the next few decades (see also the TEAP report on destruction and waste streams from the different sectors, by the Decision XX/7 Task Force). Banks of halons are also important, and are roughly split equally between non-article 5 and Article 5 countries. The size of this bank is expected to decrease. It should be noted, that recovery efforts and the associated costs may vary widely, to the extent that certain, large amounts of ODS in banks are virtually unrecoverable, although still existing. However, the option for destruction still remains open. For example, refrigerants are generally considered to be easily recoverable but recovery of foam blowing agents can be more complicated (see again the report by the Decision XX/7 Task Force). In general, emissions, i.e., bank-turnover varies significantly from application to application: from months (e.g. solvents), several years (refrigeration applications) to over half a century (foam insulation). The banks stored in equipment and foams may leak during the use phase of the products they are part of, and at the end of the product life-cycle (in case they are not recovered or destroyed) Set up of the 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report The report has Key Messages and an Abstract Executive Summary (e.g. for policy makers), both of which were extracted from the Executive Summaries for all chapters, which are presented in the beginning of the report. Where the Executive Summaries were agreed by the separate chapters, the Key Messages and the Abstract Executive Summary were circulated numerous times to all CLAs and finally amongst Committee members until full agreement was reached. This chapter 1 gives a general introduction, and describes the process how the RTOC report was put together by the members. Chapter 2 presents refrigerants and all their aspects. It elaborates on Ozone Depleting Potentials, and on ODP and GWP data for reporting purposes. It also investigates the status and research needs for data, i.e., thermophysical, heat transfer, compatibility and safety data. Chapters 3, 4, 5 and 6 deal with the food chain and investigate the technical feasibility of options. They all consider non-odp options and deal with aspects such as the use of non-fluorochemicals, the reduction of charges, energy efficiency improvements etc. Particularly the energy efficiency aspect plays an important role in chapter 3 on domestic refrigeration. Chapter 4 discusses the options for the 3 types of commercial refrigeration equipment. Chapter 5 deals with industrial refrigeration and cold storage, chapter 6 with transport refrigeration. Chapters 7 and 8 deal with air-to-air air conditioning and heat pumps for water heating. Chapter 9 deals with the various aspects of chillers, which includes important considerations on energy efficiency. Chapter 10 describes the options for mobile air conditioning; it evaluates the potential the options unsaturated HFCs (HFOs), carbon dioxide, hydrocarbons and other options will have. Chapter 11 deals with refrigerant conservation in the broadest sense; via adequate practices one can reduce the emission of (ozone depleting and global warming) refrigerants to the atmosphere (recover and recycle, containment). The names and contact details of all RTOC members (CLAs and Co-authors) as well as the names of all Contributors from outside the RTOC are all given in Annex 1. In the last RTOC meeting in December 2010, the RTOC members also agreed to attach to the report an Extract of a 2009 report on demand, banks and emissions done by ADEME/ ARMINES (Denis Clodic, CLA Chapter 4 responsible). This report has been attached as Annex 2 for information purposes only, in order to expand on the banks and emissions information available in the separate 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 27

40 chapters. This report in Annex 2 has no direct link to the separate chapters and has not been reviewed by the RTOC as a committee. It is therefore preceded by a disclaimer outlining this TOC Refrigeration, A/C and Heat Pumps Assessment Report

41 Chapter 2 Refrigerants Chapter Lead Author James M. Calm Co-author (non-rtoc) Glenn C. Hourahan Contributors Dennis R. Dorman Mark O. McLinden 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 29

42 2 Refrigerants More than 60 new refrigerants were commercialised for use either in new equipment or as service fluids (to maintain or convert existing equipment) since the 2006 assessment report. Of them, 21 obtained standardised designations and safety classifications while the remainder are marketed with only proprietary identifiers (without public disclosure of compositions or without application for standardised designations). Most of the new refrigerants are blends containing hydrofluorocarbons (HFCs) or, in some cases, blends of HFCs and hydrocarbons (HCs). Additional refrigerants, including blend components, still are being developed to enable completion of scheduled phase-outs of ozonedepleting substances (ODSs). Significant focus is on alternatives, including blend components, offering lower global warming potentials (GWPs) to address climate change. That pursuit forces more attention than in the past on flammable primarily low-flammability candidates. Considerable effort continues for examination of broader use of ammonia (NH 3, R-717), carbon dioxide (CO 2, R- 744), and HCs as well as of blends of them or them with low-gwp HFCs. Additional research seeks to increase and improve the physical, safety, and environmental data for refrigerants, to enable screening, and to optimise equipment performance. Despite the number of new introductions, approximately 20 older and new refrigerants, some of them blends, constitute the majority of usage on a global basis. Even this number is likely to decline to approximately 10 or 12 as older equipment using ODSs or high-gwp options is retired, along with need for service fluids for them, and as manufacturers converge on preferred refrigerants for the future. 2.1 Introduction This chapter discusses and provides tabular summaries for identifiers as well as physical, safety, and environmental data for refrigerants. It addresses the status of thermophysical (both thermodynamic and transport) property data and of ongoing examination of heat transfer and compatibility. This chapter does not address the suitability, advantages, and drawbacks of individual refrigerants or refrigerant groups for specific applications; such discussion is addressed for specific applications where relevant in subsequent chapters Refrigerant Progression The historic progression of refrigerants encompasses four generations based on defining selection criteria /Cal08/: 1830s-1930s whatever worked: primarily familiar solvents and other volatile fluids including ethers, R-717, R-744, sulfur dioxide (SO 2, R-764), methyl formate (HCOOCH 3, R-611), HCs, water (H 2 O, R-718), carbon tetrachloride (CCl 4, R-10), hydrochlorocarbons (HCCs), and others; many of them are now regarded as natural refrigerants s safety and durability: primarily chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), ammonia, and water s stratospheric ozone protection: primarily HCFCs (for transition use), HFCs, ammonia, water, hydrocarbons, and carbon dioxide ? global warming mitigation: still in determination, but likely to include refrigerants with very low or no ozone depletion potential (ODP), low global warming potential (GWP), and high efficiency; likely to include, at least initially, unsaturated hydrofluorocarbons (hydrofluoro-olefins, HFOs discussed below), ammonia, carbon dioxide, hydrocarbons, and water. GWP demarcation for acceptability is defined, at least initially, as having a GWP relative to CO 2 for 100 yr integration of 150 or less, predicated on European regulations for mobile air conditioning (see chapter 10). A proposed further classification scheme distinguishes between very low (or ultra-low) with GWP < ~30, very low with GWP < ~100, low with GWP < ~300, moderate with GWP < ~1000, high with GWP < ~3,000, very high with GWP < ~10,000, and ultra-high with GWP > ~10,000 /UNEP10/ TOC Refrigeration, A/C and Heat Pumps Assessment Report

43 2.1.2 Unsaturated Hydrofluorochemicals Facing regulatory pressures to eliminate refrigerants with high GWPs, and at least for automobile systems GWPs exceeding 150, the major refrigerant manufacturers have aggressively pursued unsaturated fluorochemicals. They are chemicals consisting of two or more carbon atoms with at least one double bond between two or more of them as well as fluorine, hydrogen, and possibly also chlorine or other halogens. Unsaturated fluorocarbons also are identified as fluoro-alkenes or fluoroolefins. The double carbon-carbon bond(s) make(s) the compounds more reactive. That leads to rapid decomposition in the lower atmosphere, because such fluoro-alkenes are less stable in presence of the oxidative reactants there. Some also are subject to photolytic decomposition. The result is short atmospheric lifetimes and, thereby, very low ODPs and GWPs. The unsaturated HFC (also identified as hydrofluoro-alkene or hydrofluoro-olefin, HFO) family is a focal example with varying extents of fluorination, in part as a trade-off between flammability with low fluorine content and typically increasing GWP and cost with higher fluorine content. Chemical producers are pursuing alternatives for the most widely used low-, medium-, and high-pressure refrigerants. Among the unsaturated HFCs, various HFC-1225 isomers previously pursued seem abandoned predicated on toxicity findings. HFC-1234yf (CH 2 =CFCF 3 ) in particular is being widely considered both as a single-compound refrigerant and as a blend component. Manufacturer announcements also indicate pursuit of HFC-1234ze(E) (CHF=CHCF 3 ), HFC-1243zf (CH 2 =CHCF 3 ), and other HFC-1234 and HFC-1243 isomers and enantiomers. Some manufacturers also are pursuing unsaturated HCFCs (also identified as hydrochlorofluoro-alkene or hydrochlorofluoro-olefins, HCFOs), notably HCFC-1233 isomers, to obtain similar benefits with reduced or avoided flammability, but they introduce a trade-off concern with ODP albeit extremely low. While complete data are not yet available, or publicly available due to the proprietary nature of development, the limited information already in the public domain suggests that some unsaturated hydrofluorochemicals will be technically and commercially viable. Opponents of unsaturated fluorochemicals argue, often vehemently, that they pose additional environmental or safety hazards not justified with existence of available natural refrigerant alternatives. The extent of long-term acceptability of unsaturated HFCs (HFOs) or more broadly unsaturated hydrohalochemicals is uncertain, though a number of initial studies indicate manageable environmental impacts /Leu10, Kaj10, Pap09/. The relatively recent commercial pursuit of unsaturated fluorochemicals, as well as blends of them or containing them, has catalyzed a number favourable claims but also counterclaims. More information is likely to emerge in the next assessment cycle. For now, the various application chapters that follow address consideration of specific unsaturated fluorochemicals as appropriate. Further information is likely to emerge in the next assessment cycle. 2.2 Data Summary Table 2-1 provides summary data for refrigerants both single-compound and blend addressed in this report as well as those used historically, under consideration as candidates for future use, and undergoing renewed interest (historical and now candidates for broader application). The table excludes proprietary blends for which the composition (components) and/or formulation (their proportions) have not been disclosed. The table has been updated from prior assessments to reflect current data from consensus assessments and published scientific and engineering literature where possible. The summary table also adds two new single-compound refrigerants and 21 new blends introduced since the 2006 assessment report /UNEP06/. The data in this table were extracted from more extensive summaries by Calm and Hourahan /Cal07, Cal11/, the Refrigerant Database /Cal10/, and informatory appendices to ASHRAE Standard /ASH10a/ and addenda thereto /ASH10b/. Those references provide further information on the 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 31

44 refrigerants included and address additional refrigerants. Some of the data have been updated with further revisions (later editions) of the cited sources, notably including REFPROP 9.0 /Lem10/ for thermophysical properties, though in some cases with updated fluid and mixture models for planned inclusion in future revisions. The database also identifies the sources for the data presented in the table as well as, for some refrigerants, additional data where conflicting values were reported by different investigators. The data and their limitations should be verified in the referenced source documents, particularly where use of the data would risk loss to life or property. REFPROP can be used to calculate additional properties for many of the refrigerants and additional blends TOC Refrigeration, A/C and Heat Pumps Assessment Report

45 Table 2-1: Physical, Safety, and Environmental Data for Historical, Current, and Candidate Refrigerants 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 33

46 Table 2-1: Physical, Safety, and Environmental Data for Historical, Current, and Candidate Refrigerants (continued) TOC Refrigeration, A/C and Heat Pumps Assessment Report

47 Table 2-1: Physical, Safety, and Environmental Data for Historical, Current, and Candidate Refrigerants (continued) 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 35

48 Table 2-1: Physical, Safety, and Environmental Data for Historical, Current, and Candidate Refrigerants (continued) TOC Refrigeration, A/C and Heat Pumps Assessment Report

49 The data presented, from left to right in the table are: refrigerant number, if assigned, in accordance with American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) Standard 34 /ASH10a, ASH10b/: A revision to an international standard is in preparation, but not yet final, as the primary document for designation and safety criteria /ISO05b, ISO08/, but the proposed designation systems are essentially consistent. chemical formula, in accordance with the International Union of Pure and Applied Chemistry (IUPAC) convention /IUP79/ or, for blends, the blend composition in accordance with ASHRAE Standard 34 /ASH10a, ASH10b/ molecular mass calculated /Cal11/ based on the updated IUPAC atomic weights /Wie09/ normal boiling point (NBP) or, for blends, the bubble point temperature at kpa based on REFPROP 9.0 /Lem10/ when included critical temperature (T c ) in C or, for blends, the calculated pseudo-critical temperature based on REFPROP 9.0 /Lem10/ when included Occupational Exposure Limit (OEL) such as the Threshold Limit Value (TLV) in ppm v/v assigned by the American Conference of Governmental Industrial Hygienists (ACGIH), Workplace Environmental Exposure Level (WEEL) by the American Industrial Hygiene Association (AIHA), or a consistent occupational exposure limit on a time-weighted average (TWA) basis for an 8 to 10 hr day and 40 hr work week lower flammability limit (LFL) in % concentration ambient air: Where evident, the tabulated values are those determined in accordance with ASHRAE Standard 34 /ASH10a, ASH10b/. safety classification, if assigned, in accordance with ASHRAE Standard 34 /ASH10a, ASH10b/: The leading letters A and B signify lower and higher toxicity, respectively, based on occupational exposure limits. The numbers 1, 2, and 3 indicate no flame propagation, lower flammability, and higher flammability, respectively, at specified test conditions predicated on both LFL and heat of combustion. wff signifies that the worst case of formulation and the worst case of fractionation for flammability, respectively, both as defined in /ASH10a/, is flammable in either the vapour or liquid phase. A recent modification to ASHRAE 34, also proposed for International Organization for Standardization (ISO) 817 /ISO08/, subdivides group 2 based on the burning velocity, with 2L implying those more difficult to ignite /ASH10a/. Some of the classifications are followed or replaced by lower case letters that indicate: d a prior classification was deleted and the refrigerant no longer has a safety classification p a classification assigned on a provisional basis r a recommended revision or addition as shown, but pending final approval and/or publication atmospheric lifetime (τ atm ) in years: Note that τ atm normally is not indicated for blends since it is ambiguous whether the lifetime pertains to the blend as formulated, a modified formulation as some components decompose more rapidly than others, or the most enduring component. ozone depletion potential (ODP) relative to CFC-11: ODPs indicate the relative ability of refrigerants (and other chemicals) to destroy stratospheric ozone. The values included reflect the latest scientific consensus data as adopted in the Scientific Assessment /WMO10/. Additional, consistent ODP data are included as available from references Cal10 and Cal11 for refrigerants for which consensus ODPs were not adopted. The ODPs indicated for blends are calculated mass-weighted averages /Cal10, Cal11/ based on the latest accepted IUPAC atomic weights /Wie09/ for the components. global warming potential (GWP) relative to CO 2 for 100 year integration based on the values reported in the IPCC Fourth Assessment Report /IPCC07/ and the 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 37

50 Scientific Assessment /WMO10/. The values shown are direct GWPs; indirect and net GWPs are discussed in references IPCC07 and WMO10. Additional, consistent GWP data are similarly included as available from references Cal10 and Cal11 for refrigerants for which consensus GWPs were not adopted. The GWPs indicated for blends are calculated mass-weighted averages /Cal10, Cal11/ based on the latest accepted IUPAC atomic weights /Wie09/ for the components. The GWP values shown as ~20 or <20 in Table 2-1 for hydrocarbons reflect uncertainty in calculation, for which there is no scientific consensus at this time. The approximations shown lie in the ranges of uncertainty. status: Refrigerants restricted (production limitations, phaseout, or measures to reduce releases) for environmental reasons are noted as follows: M controlled (or for blends one or more components is controlled) under the Montreal Protocol K controlled (or for blends one or more components is controlled) under the Kyoto Protocol Ozone Depletion Potentials The ODPs indicated in the Table 2-1 are semi-empirical values except for HCFC-123, for which a model-derived value was adopted in scientific assessments due to its short atmospheric lifetime /WMO10/. Semi-empirical ODPs are calculated values that incorporate adjustments for observed atmospheric measurements. This approach is conceptually more accurate than other measures, but the data needed are difficult to measure precisely and it is still evolving with further and improved measurements and understanding. There are other ODP indices, among them modelled, time-dependent, and regulatory variants /Cal07, Cal11/. Modelled data are determined by large models that calculate impacts based on decomposition paths and rates as well as atmospheric conditions including the influences of additional ozone depleting substances. Time-dependent ODPs use chemicals other than CFC-11 as the reference to emphasise impacts for other, typically shorter, timeframes. Normalising values to short-lived compounds accentuates near-term impacts, but discounts long-term effects. Time-dependent ODPs are not cited often, particularly since the release of ozone-depleting substances already has peaked and recovery of the stratospheric ozone layer is underway. Regulatory ODPs generally are old data used to set phase-out steps, determine compliance with the Montreal Protocol, and allocate production quotas in national regulations. Because of the political and competitive complexities in changing consumption targets and production allocations, these values commonly are left unchanged even when newer scientific findings improve the quantification precision. The ODP values listed in the annexes to the Montreal Protocol, for example, have not been updated since 1987 for chlorofluorocarbons (CFCs) and 1992 for hydrochlorofluorocarbons (HCFCs). A note in the Protocol indicates that the values are estimates based on existing knowledge and will be reviewed and revised periodically, but that has not happened yet /UNEP09/ ODP and GWP Data for Regulatory and Reporting Purposes The ODP and GWP data presented in Table 2-1 are based on international scientific assessments and reflect the latest consensus determinations on potential impacts. However, the reduction requirements and allocations under the Montreal Protocol, emission reductions and reporting pursuant to the Kyoto Protocol, and provisions in many national regulations pursuant to them use older, adopted values. Table 2-2 compares the latest consensus ODP data /WMO10/ to the regulatory ODPs used in the Montreal Protocol /UNEP09/. Table 2-3 similarly contrasts the latest consensus GWPs, for 100 yr integration, with those used for reporting and emission reductions under the Kyoto Protocol (from /IPCC95/) TOC Refrigeration, A/C and Heat Pumps Assessment Report

51 Table 2-2: Scientific and Regulatory ODPs for BFC, CFC, and HCFC Refrigerants ODP refrigerant scientific a regulatory B B b a ODPs indicated are as adopted in reference /WMO10/. They are semi-empirical except for HCFC-123, which is a modelled value (0.0098) based on its short atmospheric lifetime. Table 2-3: Current Consensus and Reporting GWPs for 100 yr Integration for HFC and PFC Refrigerants GWP refrigerant /WMO10/ reporting 14 7,390 6, ,200 11, ,200 9, ,420 2, a 1,370 1, a 4,180 3, a ,830 7, ea 3,580 2, fa 9,820 6,300 C318 10,300 8, TOC Refrigeration, A/C and Heat Pumps Assessment Report 39

52 2.3 Status and Research Needs for Data Thermophysical Properties The status of data for the thermophysical properties of refrigerants, which include both thermodynamic properties (such as density, pressure, enthalpy, entropy, and heat capacity) and transport properties (such as viscosity, thermal conductivity, and surface tension), is generally good. The data are sufficient to permit evaluation and testing of virtually all candidate refrigerants, with notable exception for the newer unsaturated hydrofluorochemicals (see above). Data gaps do exist, however, for the thermodynamic and transport properties of blends and less-common fluids. The thermodynamic data and models for the most-common HFCs (HFC-32, HFC-125, and HFC-134a) and HFC blends (R-404A, R-407C, R-410A, and R-507A) are generally excellent. The data often are limited for new blends. The transport data for these fluids are good for the single-compound refrigerants, but additional data and improved models are needed for the HFC and some HC blends. The thermodynamic data for HC-290 (propane), HC-600 (n-butane), and HC-600a (isobutane) are generally very good. The data for R-717 (ammonia) are not as good as commonly assumed; much of the data are old and sometimes inconsistent and/or limited in coverage. The property data for R-744 (carbon dioxide) are excellent. An international standard provides thermodynamic properties of ten single-compound refrigerants and four blends /ISO05a/. The U.S. National Institute of Standards and Technology (NIST) REFPROP database /Lem10/ implements and provides references to published models for the thermodynamic and transport properties of all of the most common refrigerants and blends. It calculates properties over wide ranges of temperature, pressure, and composition, and it is compliant with the ISO standard /ISO05a/. The data situation for the less-common fluids is more variable. There is interest in the ethers and particularly the hydrofluoroethers (HFEs) /Biv97, Sek00/. The available data for them are often scattered among obscure sources. There is a need to collect and evaluate the data for such candidates. Properties are beginning to emerge for unsaturated HFCs /for example Bro09a, Bro09b, Din10, Gre09, Hig10, Kay10, McL10, Ric10, Tan09 and Tan10/ and further studies are underway. Two such refrigerants were added to REFPROP 9.0 in 2010 /Lem10/. A major uncertainty for all of the refrigerants is the influence of lubricants on heat transfer and other properties. The working fluid in most systems is actually a mixture of the refrigerant and the lubricant carried over from the compressor(s). Research on the refrigerantlubricant mixtures is underway. It is complicated by the great variety of lubricants in use and by the often highly proprietary nature of the chemical structure or compositions of the lubricant and/or additives. In addition to impacting properties themselves (and especially viscosity and heat transfer), lubricant selections, properties, and degradation have substantial impacts on equipment wear that in-turn alters performance from predictions based on refrigerant properties Heat Transfer and Compatibility Data Refrigerant heat transfer technology has been extensively studied and documented by researchers in many countries. Two reports by Thome /Tho98a and Tho98b/ provide comprehensive reviews of evaporating and condensing heat transfer for many refrigerants TOC Refrigeration, A/C and Heat Pumps Assessment Report

53 including fluorochemicals, hydrocarbons, ammonia, and carbon dioxide. The reports cover in-tube and shell-side boiling and condensing of single-compound refrigerants, azeotropic and zeotropic blends, and refrigerant-lubricant mixtures. They address plain tubes, internally finned tubes with conventional and cross-grooved fins, and both conventional low-fin and enhanced externally-finned tubes plus falling-film evaporation. Other reviews for refrigerant heat transfer technology include Ohadi et al. /Oha96/ for ammonia, Pais and Webb /Pai91/ for pool boiling on enhanced surfaces, Cavallini et al. /Cav95/ for condensation models of refrigerants inside smooth and enhanced tubes, Darabi et al. /Dar95/ for flow boiling correlations in smooth and augmented tubes, Singh et al. /Sin95/ on electrohydrodynamic enhancement of heat transfer, and a series of articles on heat transfer of carbon dioxide, ammonia, and hydrocarbons /IIR97/. Many types of refrigeration and air-conditioning systems are operating with fluorochemical, hydrocarbon, ammonia, and carbon dioxide refrigerants, suggesting reasonably adequate refrigerant heat transfer data. The best heat transfer data availability are for fluorocarbon (now mainly HFCs) and ammonia refrigerants. From the above-mentioned reports, plus input from other researchers, the following research needs were determined: further test data for shell-side boiling and condensation of zeotropic mixtures local heat transfer data determined at specific values of vapour quality microchannel heat exchanger refrigerant-side heat transfer data including flow distribution effects effects of lubricants on heat transfer, especially for ammonia, carbon dioxide, hydrocarbons, unsaturated HCFCs, and unsaturated HFCs accurate plain tube and microfin tube evaporation and condensation data for hydrocarbons inside-tube condensation heat transfer data for carbon dioxide at low temperatures such as 20 C heat transfer correlations for carbon dioxide supercritical heat rejection and twophase evaporation Materials compatibility data are available from many sources, among them manufacturers literature (refrigerant, plastics, and elastomer manufacturers), materials chemical resistance publications, and a series of studies performed for the Materials Compatibility and Lubricants Research (MCLR) Program of the Air-Conditioning and Refrigeration Technology Institute (ARTI). The MCLR reports addressed compatibility of refrigerants and lubricants with metals, hermetic motor materials, elastomers, engineering plastics, desiccants, and lubricant additives /Cav93, Cav97, Doe93, Doe96, Fie95, Ham94, and Hut92/. The MCLR studies focused primarily on fluorochemical replacements for CFCs via sealed-tube and other laboratory tests. In general, HFCs were found to be less reactive than HCFCs such as HCFC- 22 or HCFC-123. As a result, most materials accepted as compatible with HCFCs also were deemed compatible with HFCs. A statistical study of compressors identified air as the most aggressive contaminant, forming oxidised lubricant products, based on tests for non-ideal contaminant conditions (with added water, air, and organic acids) /Cav00/. Additionally, water and acid development with air affected overall mechanical performance /Cav00/. The study suggests that further compatibility studies may be needed for non-ideal conditions. While actual data are as yet very limited, unsaturated halochemicals (for example unsaturated HFCs HFOs) may be less thermally stable at compressor operating temperatures. Limited studies report favourable stability in anhydrous, air free, sealed tube tests /Lec09/, but decomposition or corrosion effects particularly in the presence of common contaminant levels in actual systems need further study TOC Refrigeration, A/C and Heat Pumps Assessment Report 41

54 A major source of materials compatibility data for carbon dioxide, ammonia, and hydrocarbons are three chemical resistance guides by Pruett covering metals, elastomeric compounds, and engineering plastics /Pru83, Pru94, and Pru95/. Since plastics and elastomers contain many types of additives (most of them proprietary), specific materials should be tested to ensure compatibility. Ammonia is incompatible with most types of electrical wiring insulation. Metals inside ammonia systems normally are limited to stainless and carbon steel, but two publications from Germany /Kna97 and Lip97/ report good compatibility of ammonia with copper and copper alloys in systems with careful moisture control, as water intrusion can result in severe copper corrosion. Aluminium is compatible with pure (dry) ammonia, but it is sensitive to corrosion in water circuits due to the presence of chlorides. Aqueous solutions of ammonia cause corrosion that puts aluminium components at risk, but coatings may offer corrosion prevention /Eur00/. Further study is needed to determine the precise levels of moisture of concern with consideration of the dissimilar levels of hygroscopicity of different lubricants. A materials issue with carbon dioxide is explosive decompression with elastomers, especially in systems with pressure cycling. Carbon dioxide is very soluble in many types of elastomers, and if it cannot diffuse out of the elastomer quickly enough, bubbles of gas may grow and cause rupture of the elastomer shapes, such as o-ring seals. Explosive decompression can be minimised by selecting elastomers with appropriate mechanical properties and tear strength, a low carbon dioxide solubility coefficient, and a high carbon dioxide diffusion coefficient /Har99/. Sealed tube tests containing HC-290 (propane) and HC-600a (isobutane) with various oils, materials, and air show negligible degradation /San96/. In further sealed tube tests, a variety of elastomers were tested with an R-290/600a blend or HC-601 (n-pentane) with a mineral or polyolester (POE) oil; Buna N, hydrogenated nitrile butadiene rubber (HNBR), Viton, and neoprene performed well while natural, silicon, and ethylene propylene diene terpolymer (EPDM) rubbers were less suitable /Col00/. Impurities at the level of 3% in HC-290 were found to not affect performance within measurement uncertainties, provided that the levels of sulfur, water, and unsaturated hydrocarbons were strictly limited /Kru97/ Safety Data The primary hazards from refrigerant handling and use arise from pressure explosions, toxicity, flammability, and air displacement, the last of which may lead to oxygen deprivation and asphyxiation /Cal94/. Pressure data are generally well characterised as necessary for component and system design. Safety standards such as American National Standards Institute / American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ANSI/ASHRAE) 15, Safety Standard for Refrigeration Systems /ASH10c/, which is the basis of many national and international standards and regulations, provide guidance on vessel requirements, pressure relief devices, and testing. Toxicity concerns arise from both accidental releases and occupational handling, for example to install, service, and remove equipment /Cal94 and Cal96/. The data are divided into acute (short-term, single exposure) and chronic (long-term, possibly repeated exposure). Key acute effects include lethality, cardiac sensitisation, central nervous system (CNS) or anesthetic effects, and others that may impair the ability to escape or cause permanent injury. Most of these effects arise from inhalation rather than contact or ingestion, since a desirable attribute of refrigerants is that they be volatile compounds and, as a result, either are vapours at typical conditions or vaporise quickly in contact with body temperatures. Accordingly, it is hard to TOC Refrigeration, A/C and Heat Pumps Assessment Report

55 have extended contact or to ingest sufficient quantities before inhalation effects come into play. Exceptions are refrigerants that irritate or corrode the skin. Safety data and resulting recommendations for refrigerant concentration limits and occupational exposure limits generally are available for fluorochemical refrigerants /Cal00, Cal07, and Cal10/. The data typically are developed, primarily through animal testing, by manufacturers in the course of qualifying new candidates. A collaborative effort among manufacturers, the Programme for Alternative Fluorocarbon Toxicity Testing (PAFT), developed extensive data for new fluorochemical replacements for CFCs /PAF95 and PAF96/. Data are less readily available for hydrocarbons and generally are sparse for exposures above fire hazard concentrations, though toxic effects from hydrocarbons generally are not manifest below them /Kir76/. The risks inherent to testing flammable mixtures and historical presumption that application exposures will be kept below the LFL both mitigate against testing higher concentrations. Extensive data are available for ammonia /Cle90 and Syr90/ and carbon dioxide /NIO76/, though much of it predates currently accepted toxicity test criteria and results in conflicts from early tests with primitive laboratory methods and contaminated samples. Further data are needed for fluoroether and hydrofluoroether candidates /Biv97 and Sek00/ and for unsaturated fluorochemicals. Flammability data generally are available /Ric92, Cal07, ASH10a/, though data dispersion from different test methods and laboratories leads to a degree of uncertainty in some cases. 2.4 References /ASH10a/ Designation and Safety Classification of Refrigerants, ANSI/ASHRAE Standard , American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), Atlanta, GA, USA, 2010 /ASH10b/ Designation and Safety Classification of Refrigerants, ANSI/ASHRAE Addenda a, b, and d to ANSI/ASHRAE Standard , American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), Atlanta, GA, USA, 2010 /ASH10c/ Safety Standard for Refrigeration Systems, ANSI/ASHRAE Standard , American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), Atlanta, GA, USA, 2010 /Biv97/ D. B. Bivens and B. H. Minor, Fluoroethers and Other Next-Generation Fluids, Refrigerants for the 21 st Century (proceedings of the ASHRAE/NIST Refrigerants Conference, Gaithersburg, MD, 6-7 October 1997), American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE), Atlanta, GA, USA, , 1997; International Journal of Refrigeration, 21(7): , 1998 /Bro09a/ J. S. Brown, C. Zilio, and A. Cavallini, Estimations of the Thermodynamic and Transport Properties of R-1234yf Using a Cubic Equation of State and Group Contribution Methods, Proceedings of the 3 rd IIR Conference on Thermophysical Properties and Transfer Processes of Refrigerants (Boulder, CO, USA, June 23-26, 2009), International Institute of Refrigeration, Paris France, and the National Institute of Standards and Technology (NIST), Boulder, CO, USA, paper 127, June 2009 /Bro09b/ J. S. Brown, HFOs: New, Low Global Warming Potential Refrigerants, ASHRAE Journal, 51(8):22-29, August 2009 /Cal94/ J. M. Calm, Refrigerant Safety, ASHRAE Journal, 36(7):17-26, July TOC Refrigeration, A/C and Heat Pumps Assessment Report 43

56 /Cal96/ J. M. Calm, The Toxicity of Refrigerants, Proceedings of the 1996 International Refrigeration Conference at Purdue (23-26 July 1996), Purdue University, West Lafayette, IN, USA, , July 1996 /Cal00/ J. M. Calm, Toxicity Data to Determine Refrigerant Concentration Limits, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute (ARTI), Arlington, VA, USA, September 2000 /Cal07/ J. M. Calm and G. C. Hourahan, Refrigerant Data Summary Update, HPAC Engineering, 79(1):50-64, January 2007 /Cal08/ J. M. Calm, The Next Generation of Refrigerants Historical Review, Considerations, and Outlook, International Journal of Refrigeration, 31(7): , November 2008 /Cal10/ J. M. Calm, Refrigerant Database, Air-Conditioning and Refrigeration Technology Institute (ARTI), Arlington, VA, USA, July 2001 and unpublished updates thereto though 2010 /Cal11/ J. M. Calm and G. C. Hourahan, Physical, Safety, and Environmental Data Summary for Current and Alternative Refrigerants, Proceedings for the 23 rd International Congress of Refrigeration (Prague, Czech Republic, August 2011), International Institute of Refrigeration (IIR), Paris, France, 2011 (in preparation) /Cav93/ R. C. Cavestri, Compatibility of Refrigerant and Lubricants with Engineering Plastics, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, September 1993, revised December 1993 /Cav95/ A. Cavallini et al., Condensation of New Refrigerants Inside Smooth and Enhanced Tubes, Proceedings of the 19 th International Congress of Refrigeration (The Hague, The Netherlands, August 1995), International Institute of Refrigeration (IIR), Paris, France, IVa: , 1995 /Cav97/ R. C. Cavestri et al., Compatibility of Lubricant Additives with HFC Refrigerants and Synthetic Lubricants (Final Report, Part 1), report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, July 1997 /Cav00/ R. C. Cavestri, Effect of Selected Contaminants in Air Conditioning and Refrigeration Equipment (Final Report), report ARTI MCLR DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, 2000 /Cle90/ Clement Associates, Incorporated, Health Effects Assessment for Ammonia, The Fertilizer Institute, Washington, DC, USA, February 1990 /Col00/ D. Colbourne and T. J. Ritter, Compatibility of Non-Metallic Materials with Hydrocarbon Refrigerant and Lubricant Mixtures, Proceedings of the 4 th IIR-Gustav Lorentzen Conference Natural Working Fluids (25-28 July 2000), Purdue University, West Lafayette, IN, USA, , 2000 /Dar95/ J. Darabi, M. Salehi, M.H. Saeedi and M. M. Ohadi, Review of Available Correlations for Prediction of Flow Boiling Heat Transfer in Smooth and Augmented Tubes, paper CH , Transactions (Winter Meeting, Chicago, IL, USA, 28 January 1 February 1995), American Society of Heating, Refrigeration, and Air-Conditioning Engineers, Atlanta, GA, USA, 101(1): , 1995 /Din10/ G. Di Nicola, M. Pacetti, F. Polonara, and G. Santori, P V T Behavior of 2,3,3,3- Tetrafluoroprop-1-ene (HFO-1234yf) in the Vapor Phase from 243 to 373 K, Journal of Chemical and Engineering Data, 55(9): , 2010 /Doe93/ R. G. Doerr and S. A. Kujak, Compatibility of Refrigerants and Lubricants with Motor Materials, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, May 1993 /Doe96/ R. G. Doerr and T. D. Waite, Compatibility of Refrigerants and Lubricants with Motor Materials under Retrofit Conditions, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, October TOC Refrigeration, A/C and Heat Pumps Assessment Report

57 /Eur00/ /Fie95/ /Gre09/ /Ham94/ /Har99/ /Hig10/ /Hut92/ /IIR97/ /IPCC95/ /IPCC05/ /IPCC07/ /ISO05a/ /ISO05b/ Eurammon, Aluminum as Construction Material in Ammonia Refrigeration Cycles, information bulletin 10, Frankfurt, Germany, J. E. Field, Sealed Tube Comparisons of the Compatibility of Desiccants with Refrigerants and Lubricants, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, May 1995 A. J. Grebenkov, R. Hulse, H. Pham, and R. Singh, Physical Properties and Equation of State for Trans-1,3,3,3-Tetrafluoropropene, Proceedings of the 3 rd IIR Conference on Thermophysical Properties and Transfer Processes of Refrigerants (Boulder, CO, USA, June 2009), paper 191, International Institute of Refrigeration, Paris France, and the National Institute of Standards and Technology (NIST), Boulder, CO, USA, June 2009 G. R. Hamed, R. H. Seiple, and O. Taikum, Compatibility of Refrigerant and Lubricants with Elastomers, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, January 1994 C. Harrison, Keeping CO 2 Where It Belongs. Requirements for Sealing Future Automotive Climate Control Systems, Meeting Results and Presentations, SAE International Automotive Alternate Refrigerant Systems Symposium, Scottsdale, AZ, USA, 28 June 1 July 1999 Y. Higashi, Thermophysical Properties of HFO-1234yf and HFO-1234ze(E), Proceedings of the International Symposium on Next-Generation Air Conditioning and Refrigeration Technology (Tokyo, Japan), New Energy and Industrial Technology Development Organization (NEDO), Kawasaki City, Kanagawa Prefecture, Japan, February 2010 D. F. Huttenlocher, Chemical and Thermal Stability of Refrigerant-Lubricant Mixtures with Metals, report DOE/CE/ , Air-Conditioning and Refrigeration Technology Institute, Arlington, VA, USA, 9 October 1992 Heat Transfer Issues in Natural Refrigerants (proceedings of the IIR Conference meeting of Commissions B1, E1, and E2, University of Maryland, College Park, MD, USA, 6-7 November 1997), publication 1997/5, International Institute of Refrigeration, Paris, France, 1997 Intergovernmental Panel on Climate Change (IPCC) of the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), Climate Change 1995 Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change, edited by J. T. Houghton, L. G. Meira Filho, B. A. Callander, N. Harris, A. Kattenberg, and K. Maskell, Cambridge University Press, Cambridge, UK, 1996 Intergovernmental Panel on Climate Change (IPCC) and the Technology and Economic Assessment Panel (TEAP), Safeguarding the Ozone Layer and the Global Climate System: Issues Related to Hydrofluorocarbons and Perfluorocarbons, World Meteorological Organization (WMO), Geneva, Switzerland, and the United Nations Environment Programme (UNEP) Ozone Secretariat, Nairobi, Kenya, 2005 Intergovernmental Panel on Climate Change (IPCC) of the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), Climate Change 2007: The Scientific Basis Contribution of Working Group I to the IPCC Fourth Assessment Report, edited by S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller, Cambridge University Press, Cambridge, UK, and New York, NY, USA, 2007 Refrigerant Properties, ISO standard 17584:2005, International Organization for Standardization (ISO), 2005 Refrigerants Designation System, ISO standard 817:2005, International Organization for Standardization (ISO), Geneva, Switzerland, 15 January TOC Refrigeration, A/C and Heat Pumps Assessment Report 45

58 /ISO08/ Refrigerants Designation and Safety Classification, ISO working document ISO/DIS 817:2008, International Organization for Standardization (ISO), Geneva, Switzerland, 1 February 2008 /IUP79/ International Union of Pure and Applied Chemistry (IUPAC), Nomenclature of Organic Chemistry, Sections A, B, C, D, E, F, and H, prepared by J. Rigaudy and S. P. Klesney, Pergamon Press Incorporated, New York, NY, USA, 1979 /Kaj10/ H. Kajihara et al., Estimation of environmental concentrations and deposition fluxes of R- 1234yf and its decomposition products emitted from air conditioning equipment to atmosphere, paper NS24, Proceedings of the 2010 International Symposium on Next- Generation Air Conditioning and Refrigeration Technology, Tokyo, Japan, February 2010 /Kay10/ Y. Kayukawa, K. Fujii, R. and Akasaka, Thermodynamic Property Measurements for HFO 1234yf and its Binary Mixtures, Proceedings of the International Symposium on Next-Generation Air Conditioning and Refrigeration Technology (Tokyo, Japan), New Energy and Industrial Technology Development Organization (NEDO), Kawasaki City, Kanagawa Prefecture, Japan, February 2010 /Kir76/ C. J. Kirwin, Toxicological Review of Propane, Butane, Isobutane, Pentane, and Isopentane, Phillips Petroleum Company, Bartlesville, OK, USA, November 1976 /Kna97/ M. Knabe, S. Reinhold, and J. Schenk, Ammoniakanlagen und Kupfer-Werkstoffe? [Ammonia Systems and Cuprous Materials?], Ki Luft und Kältetechnik, 33(9): , 1997 /Kru97/ H. H. Kruse and T. Tiedemann, Experience with HC Refrigerants and Projections for Future Applications, Refrigerants for the 21st Century (proceedings of the ASHRAE/NIST refrigerants conference, Gaithersburg, MD, USA, 6-7 October 1997) American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, GA, USA, 44-56, 1997 /Lec09/ Leck, T. J., Evaluation of HFO-1234yf as a Potential Replacement for R-134a in Refrigeration Applications, Proceedings of the 3 rd IIR Conference on Thermophysical Properties and Transfer Processes of Refrigerants (Boulder, CO, USA, June 23-26, 2009), International Institute of Refrigeration, Paris France, and the National Institute of Standards and Technology (NIST), Boulder, CO, USA, paper 155, June 2009 /Lem10/ E. W. Lemmon, M. L. Huber, and M. O. McLinden, NIST Standard Reference Database 23, NIST Reference Fluid Thermodynamic and Transport Properties REFPROP (version 9.0), Standard Reference Data Program, National Institute of Standards and Technology (NIST), Gaithersburg, MD, USA, 2010 /Leu10/ D. J. Luecken, R. L. Waterland, S. Papasavva, K. N. Taddonio, W. T. Hutzell, J. P. Rugh, and S. O. Andersen, Ozone and TFA Impacts in North America from Degradation of 2,3,3,3-Tetrafluoropropene (HFO-1234yf), A Potential Greenhouse Gas Replacement, Environmental Science and Technology, 44(1): 44, , 2010 /Lip97/ H. Lippold, Kupferwerkstoffe in Ammoniakanlagen [Cuprous Materials in Ammonia Systems], KK Die Kälte- und Klimatechnik, 50(10): , October 1997 /McL10/ M. O. McLinden, M. Thol, and E. W. Lemmon, Thermodynamic Properties of trans- 1,3,3,3-Tetrafluoropropene [R1234ze(E)]: Measurements of Density and Vapor Pressure and a Comprehensive Equation of State, Proceedings of the International Refrigeration and Air Conditioning Conference at Purdue, Purdue University, West Lafayette, IN, USA, July /NIO76/ Criteria for a Recommended Standard Occupational Exposure to Carbon Dioxide, publication , National Institute of Occupational Safety and Health (NIOSH), U.S. Department of Health and Human Services, Cincinnati, OH, USA, August 1976 /Oha96/ M. M. Ohadi, S. S. Li, R. K. Radermacher, and S. V. Dessiatoun, Critical Review of Available Correlations for Two-Phase Flow Heat Transfer of Ammonia, International Journal of Refrigeration, 19(4): , May TOC Refrigeration, A/C and Heat Pumps Assessment Report

59 /PAF95/ Programme for Alternative Fluorocarbon Toxicity Testing (PAFT) Toxicology Summaries, PAFT, Washington, DC, USA, September 1995 /PAF96/ Testing to Extremes Industry's Cooperative Effort to Test the Health and Safety of Selected Fluorocarbon Alternatives to CFCs, Programme for Alternative Fluorocarbon Toxicity Testing (PAFT), Washington, DC, USA, circa 1996 /Pai91/ C. Pais and R. L. Webb, Literature Survey of Pool Boiling on Enhanced Surfaces, technical paper 3444 (392-RP), Transactions (Winter Meeting, New York, NY, USA, January 1991), American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Atlanta, GA, USA, 97(1):79-89, 1991 /Pap09/ S. Papasavva, D. J. Luecken, R. L. Waterland, K. N. Taddonio, and S. O. Andersen, Estimated 2017 Refrigerant Emissions of 2,3,3,3-tetrafluoropropene (HFC-1234yf) in the United States Resulting from Automobile Air Conditioning, Environmental Science and Technology, 43(24): , 2009 /Pru83/ K. M. Pruett, Compass Corrosion Guide (Guide to Chemical Resistance of Metals and Engineering Plastics), Compass Publications, La Jolla, CA, USA, 1983 /Pru94/ K. M. Pruett, Chemical Resistance Guide for Elastomers II, Compass Publications, La Mesa, CA, USA, 1994 /Pru95/ K. M. Pruett, Chemical Resistance Guide for Metals and Alloys, Compass Publications, La Mesa, CA, USA, 1995 /Ric92/ R. G. Richard and I. R. Shankland, Flammability of Alternative Refrigerants, ASHRAE Journal, 34(4):20,22-24, April 1992 /Ric10/ M. Richter, M. O. McLinden, and E. W. Lemmon, Thermodynamic Properties of 2,3,3,3- Tetrafluoroprop-1-ene (R1234yf): p-rho-t Measurements and an Equation of State, Journal of Chemical and Engineering Data, in press, 2010 /San96/ P. Sansalvadore, M. Zgliczynski, and F. Agricola, Chemical-Physical Aspects in Refrigeration with Isobutane, Applications for Natural Refrigerants (proceedings of the IIR Conference meeting of Commissions B1, B2, E1, and E2, Aarhus, Denmark, 3-6 September 1996), publication , International Institute of Refrigeration (IIR), Paris, France, , 1996 /Sek00/ A. Sekiya and S. Misaki, Hydrofluoroethers as Alternatives to CFCs, HCFCs, HFCs, and PFCs, Conference Proceedings of the Earth Technologies Forum (Conference on Climate Change and Ozone Protection, Washington, DC, 30 October - 1 November 2000), International Climate Change Partnership and the Alliance for Responsible Atmospheric Policy, Arlington, VA, USA, , October 2000 /Sin95/ A. Singh, M. M. Ohadi, S. Dessiatoun, and W. Chu, In-Tube Boiling Heat Transfer Coefficients of R-123 and their Enhancement Using the EHD Technique, Journal of Enhanced Heat Transfer, 2(3): , 1995 /Syr90/ Syracuse Research Corporation, Toxicological Profile for Ammonia, report TP-90-03, Agency for Toxic Substances and Disease Registry (ATSDR), Public Health Service, U.S. Department of Health and Human Services, Washington, DC, USA, December 1990 /Tan09/ K. Tanaka, Y. Higashi, and R. Akasaka, Measurements of the Isobaric Specific Heat Capacity and Density for HFO-1234yf in the Liquid State, Journal of Chemical and Engineering Data, 55(2): , 2010 /Tan10/ K. Tanaka and Y. Higashi, Thermodynamic properties of HFO-1234yf (2,3,3,3- tetrafluoropropene), International Journal of Refrigeration, 33(3): , May 2010 /Tho98a/ J. R. Thome, Boiling and Evaporation of Fluorocarbon and Other Refrigerants: A Stateof-the-Art Review, Air-Conditioning and Refrigeration Institute, Arlington, VA, USA, October 1998 /Tho98b/ J. R. Thome, Condensation of Fluorocarbon and Other Refrigerants: A State-of-the-Art Review, Air-Conditioning and Refrigeration Institute, Arlington, VA, USA, October TOC Refrigeration, A/C and Heat Pumps Assessment Report 47

60 /UNEP06/ 2006 Report of the Refrigeration, Air-Conditioning and Heat Pumps Technical Options Committee, United Nations Environment Programme (UNEP), Nairobi, Kenya, January 2007 /UNEP09/ Handbook for the Montreal Protocol on Substances that Deplete the Ozone Layer (Eighth Edition), United Nations Environment Programme (UNEP), Ozone Secretariat, Nairobi, Kenya, 2009 /UNEP10/ Technology and Economic Assessment Panel 2010 Progress Report: Assessment of HCFCs and Environmentally Sound Alternatives and Scoping Study on Alternatives to HCFC Refrigerants under High Ambient Temperature Conditions, Volume 1 (Decisions XXI-9 and XIX-8 Task Force Reports), United Nations Environment Programme (UNEP), Ozone Secretariat, Nairobi, Kenya, May 2010 /Wie09/ M. E. Wieser and M. Berglund for the International Union of Pure and Applied Chemistry (IUPAC) Commission on Atomic Weights and Isotopic Abundances, Atomic Weights of the Elements 2007 (IUPAC Technical Report), Pure and Applied Chemistry, 81(11): , November 2009 /WMO10/ Scientific Assessment of Ozone Depletion: 2010, report 52, World Meteoro-logical Organization (WMO), Global Ozone Research and Monitoring Project, Geneva, Switzerland; National Oceanic and Atmospheric Administration (NOAA), Washington, DC, USA; National Aeronautics and Space Administration (NASA), Washington, DC, USA; United Nations Environment Program (UNEP), Nairobi, Kenya; and the European Commission, Research Directorate General, Brussels, Belgium; January 2011 (revised printed version in press with expected publication in March 2011) TOC Refrigeration, A/C and Heat Pumps Assessment Report

61 Chapter 3 Domestic Refrigeration Chapter Lead Author Ed McInerney Co-Authors Martien Janssen Paulo Vodianitskaia 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 49

62 3 Domestic Refrigeration 3.1 Introduction Approximately 100 million domestic refrigerators and freezers are produced annually. Most of these are used for food storage in dwellings. Beverage dispensing machines represent a small fraction of these total units. Typical storage volumes range from 20 to 850 liters/unit. Various fundamental design approaches and consumer convenience features are included within the product offerings. A typical product contains a factory-assembled, hermetically sealed, vapour-compression refrigeration system employing a 50 to 250 watt induction motor and containing 50 to 250 grams of refrigerant. Niche market products in some cases employ alternative technologies to vapour-compression refrigeration. The age distribution of the global installed products is extremely broad /Wes97/ with median age estimates ranging from 9 to 19 years at retirement. Long product life and high volume annual production combine for an estimated 1500 to 1800 million unit global installed inventory. 3.2 Options for New Equipment HFC-134a or HC-600a (isobutane) continue to be the options for domestic refrigeration new production. No new alternatives have matured to become energy-efficient, cost-competitive opportunities for these products. New, or original equipment manufacturing production conversion from use of ODS alternatives was essentially completed by The conversion trend and refrigerant selection is shown graphically in Figure 3-1. HC-290 usage in blends with HC-600a has been included with HC-600s usage in this Figure and data has not been normalised to be independent of production volumes. Refrigerant conversion to HC-600a is expected to continue, driven by conversion from HFC-134a usage. This is discussed below in section TOC Refrigeration, A/C and Heat Pumps Assessment Report

63 Field service conversion to non-ods alternatives continues to lag new product conversion. This is a consequence of long product life and the absence of drop-in substitutes for the refrigerants used in the pre-conversion production units still in service. Future product configurations will incorporate evolutionary energy efficiency improvements. These will directly influence energy-related emissions. Design approaches for environmentally responsible product disposal or recycling at end-of-life retirement is also a topic of accelerating interest Refrigerant Options As stated above, HFC-134a and HC-600a continue to be the options for domestic refrigeration new production. Throughout this chapter, HC-600a discussions include both HC-600a and binary blends of HC-600a and HC-290. In situations where capital resources are constrained, the use of binary hydrocarbon blends allow matching the volumetric capacity of previously used CFC-12 to avoid investments required to modify compressor manufacturing tools. These blends result in a small reduction in thermodynamic efficiency versus pure HC-600a and could migrate to use of pure HC-600a as capital funds become available. Two industry dynamics are of interest: (1) second-generation non-ods refrigerant usage shift from HFC- 134a to HC-600a, and (2) preliminary suggestions of low GWP unsaturated fluorocarbons to displace HFC-134a usage. Binary hydrocarbon blends can also be used when converting from HFC-134a to hydrocarbon refrigerants to match the volumetric capacity of currently used compressors and avoid manufacturing investment Non-ODS Refrigerant Usage Conversion from HFC-134a to HC-600a European production of American style refrigerators began conversion from HFC-134a to HC-600a in the early 2000 s. Initial conversions of new production automatic defrost refrigerators in Japan from HFC-134a to HC-600a were discussed in the 2006 report of this committee /UNEP06/ It is estimated that this conversion, motivated by global warming considerations, has progressed to include the majority of new refrigerator production in Japan. Recently a major U.S. manufacturer announced its intent to introduce auto-defrost refrigerators using HC-600a refrigerant to the U.S. market. This introduction represents a significant departure from current North American practices for domestic refrigeration. U.S. codes and standards interpretations and modifications required for broad use of HC-600a refrigerant are currently in process. Commercial introduction occurred during Concurrently, the number of HC-based refrigerator models offered by manufacturers based in countries such as Brazil is rising as well. The trend of conversion to hydrocarbon refrigerants will continue in the opinion of the authors. Excluding any influence from government regulatory intervention, a ten-yearhorizon estimate is that 75% of new refrigerator production will use HC-600a and 25% will use HFC-134a by 2020 /UNEP10/. This estimate is based on the assumptions: All current HC-600a applications will continue. One-half of HFC-134a applications in geographic areas where forced convection, auto defrost refrigerators are the typical configuration will convert to either HC-600a or a binary hydrocarbon blend having matched volumetric capacity to HFC-134a. Three-fourths of HFC-134a applications in geographic areas where natural convection and/or manual defrost refrigerators are the typical configuration will convert to HC-600a or a binary hydrocarbon blend TOC Refrigeration, A/C and Heat Pumps Assessment Report 51

64 Conversions will be influenced by regional market or climate change policy choices. Government regulatory influence was not considered. Substitution will be on an equal-molar basis, i.e. 100 grams of HFC-134a will be replaced by 57 grams of HC-600a. Technology to accomplish conversions is readily available. The rate and extent of conversion will be influenced by premium product cost to maintain product safety with introduction of flammable refrigerants. Premium costs are introduced by modified electrical components, increased use of reduced voltage to avoid electrical arcing and any specified redundant safety devices. Cost pressures will be more significant on model offerings with lower profit margins subject to erosion. These will typically be less-featured, lower-end models. Conversion of currently installed refrigerators to refrigerants with different characteristics can be problematic. Conversion is not recommended without the oversight and endorsement of the original manufacturer Consideration of Low-GWP Unsaturated Fluorocarbon Refrigerants Chemical manufacturers developed low atmospheric life unsaturated HFC compounds to replace HFC-134a in automotive air conditioning applications. These unsaturated fluorocarbons are developmental products and evaluation of their use in stationary applications has begun but is not being pursued with high priority. A preliminary, theoretical assessment is that HFC-1234yf has the potential for comparable efficiency to HFC-134a in domestic refrigerators. Numerous application criteria have not yet been addressed: thermal stability, hermetic system chemical compatibilities, process fluid compatibilities, contamination sensitivities, etc. Long-term reliability expectations for domestic refrigeration use are significantly more demanding than automotive applications. Much new information is required before this refrigerant can be established as a viable alternative candidate. However, the low GWP and reduced flammability versus HC-600a justify continued attention Not-In-Kind Alternative Technologies Alternative refrigeration technologies continue to be pursued for applications with unique drivers such as very low noise, portability or no access to electrical energy distribution network. Technologies of interest include Stirling cycle, absorption and adsorption cycles, thermoelectric, magnetic and trans-critical CO 2. In the absence of unique drivers such as the examples cited above, no identified technology is cost or efficiency competitive with conventional vapour-compression technology for mass-produced domestic refrigeration equipment. Absorption refrigeration equipment has been used in hotel mini-bar units due to low noise levels and for mobile, off-network applications such as campers or mobile homes for many years. Thermoelectric or Stirling cycle technologies are used for portable refrigerated chests in applications such as medical transport. Equipment for trans-critical CO 2 use of Stirling cycle technology is developed and available for limited quantity usage in applications such as packaged beverage vending machines. This technology is not considered a logical candidate for domestic refrigeration because of very small compressor swept volume requirements, reduced thermal efficiency and higher system cost versus current practice /Bee08/. Magnetic refrigeration is considered a conceptual development topic and is premature for consideration as a viable alternative. The remaining specialty niche product areas cited above would each require high capital investment to establish mass production capability. These product technologies will not be further discussed in this report focused on options for mass produced markets TOC Refrigeration, A/C and Heat Pumps Assessment Report

65 3.2.3 Product Energy Efficiency Improvement Technologies The energy efficiency of domestic refrigeration products is a topic of accelerating consumer and regulatory interest. Relative energy efficiency provides direct linkage to relative energyrelated global warming of refrigeration technology options via power consumed during the product useful life. A more extended discussion of efficiency improvement options was included in the 2002 report of this committee /UNE02/. Additional comments are contained in reports under the Eco-Design Directive studies /Eco06/. These studies provided capability background used for updating European minimum energy efficiency standards /EU09/. Significant technology options to improve product energy efficiency have already demonstrated mass production feasibility and robust, long-term reliability. Both mandatory and voluntary energy efficiency regulation programs catalysed industry product efficiency development efforts. Various energy test procedures have the intent to predict consumer energy consumption. Though standardisation activities aiming at a universal test protocol are in progress /IEC59M/, currently each test procedure is unique and the results from one should never be directly compared to results from another. A number of improved energy efficiency design options are fully mature, and future improvements of these options are expected to be evolutionary. Examples of these options include efficient compressors, high efficiency heat exchangers, improved low thermal loss cabinet structures and gaskets, and less variable manufacturing processes. Extension of these to all global domestic refrigeration would yield significant benefit, but is generally constrained by availability of capital funds. Similarly, retooling compressor manufacturing facilities would allow recovery of the minor efficiency penalties incurred with the use of HC-600a/HC290 blends versus pure HC-600a. Design options with less economic justification are sometimes introduced in premium-cost models having incentive subsidies. This provides the opportunity to mature new efficiency technologies and progress them through their individual cost/experience curves. This increases the likelihood for migration of the efficiency technologies to more cost-sensitive model line segments. Options that presently have limited or newly introduced application include variable speed compressors; intelligent controls; system reconfigurations, such as dual evaporators; advanced insulation systems; and Demand Side Management (DSM) initiatives requiring interactive communication with energy providers. The premium-cost of these options currently restrict their application to high-end models and constrain their proliferation for general use. Variable capacity compressors avoid cycle losses and inertial losses through modulating capacity and compressor speed. Use of higher efficiency permanent magnet or linear motors is also enabled by electronic commutation controls. Intelligent, adaptive controls allow variable control algorithms that avoid optimising at seldom-experienced worst-case conditions. Parallel dual evaporators can improve Carnot theoretical efficiency by effectively reducing required pressure ratios of the higher temperature evaporator. Cost effective, reliable and stable system controls need to be demonstrated. Advanced vacuum panel insulation concepts have been selectively used for several years in Japan, Western Europe and the United States. Their premium cost has constrained extension to general use. Power line load management initiatives reduce energy service provider peak load demands. Early embodiments created intermittent loss of product function and resulted in consumer dissatisfaction. More recent developments provide utilitytriggered feature constraint or capacity reduction of the product TOC Refrigeration, A/C and Heat Pumps Assessment Report 53

66 3.3 Options for Existing Equipment Service conversion to non-ods refrigerants has significantly lagged original equipment conversion. The distributed, individual proprietor character of the service industry resists coordinated efforts to convert from ODS refrigerants. Field service procedures typically use originally specified refrigerants. Refrigerant blends developed specifically for use as drop-in service alternatives have had limited success. Their acceptance has been good in regions with mandatory service regulations promoting their use. Blend selection appears to be more related to provider distribution strength than technical performance. The interested reader is referred to the 1998 report of this committee for an extended discussion of field repair and conversion options /UNEP98/. Chapter 2 in this current report contains an updated listing of refrigerant blend options. Non Article 5 countries completed conversions of new equipment production to non-ods substances approximately 15 years ago. The final production ODS-containing products are now approaching the end of their life cycle, transitioning this to a sunset issue in these countries. In Article 5 countries, service demand for ODS refrigerants is expected to remain strong for more than ten-years as a result of their later conversion to non-ods refrigerants. Limited capital resources also favour rebuilding service options in Article 5 countries versus replacement by new equipment. This further delays installation of new production units employing non-ods refrigerants. Rebuilding has the accompanying consequence of voiding the opportunity to significantly improve product energy efficiency and reduce stress on the power distribution grid. Unless there is governmental intervention, service refrigerant demand for CFC-12 is expected to continue for legacy products Drop-In Conversion of In-Service Products Drop-in conversion of existing in-service units to alternative refrigerants has been limited. Consumer safety consideration requires that any potential for flammable fluid accumulation within an enclosed volume must avoid the potential within that volume for an electrical spark, electrical arc or surface temperature above the auto-ignition temperature of the leaked gas in air. The extent of in-service product modification to assure this is dependent upon the original product configuration. The original equipment manufacturer is most familiar with the product construction and should be consulted for required modifications prior to decision to proceed. Cold-wall-evaporator constructions require leaking refrigerant to diffuse through the refrigerator inner liner or flow by convection through apertures in the liner in order to accumulate within the cooled volume. There is a very low probability of significant gas accumulation. Additionally, electrical components located within the cooled volume are limited and consequently there is a low probability of an ignition source within the enclosed volume. Economical drop-in conversion of this configuration is alleged to be viable by some spokesmen, but procedure definition by the original manufacturer should be sought prior to decision to proceed Thin-wall evaporators positioned within the cooled volume are a common construction for automatic-defrost refrigerators. Leakage of refrigerant can accumulate within the cooled volume and the risk of ignition is dependent on whether the rate of leakage is sufficient to result in a combustible mixture within the cooled volume. Additionally, electrical components are commonly located within the cooled volume -- thermostats, convective fans, radiant defrost heaters, lights, icemakers, etc. providing an elevated probability of an ignition source being present. The viability of a drop-in conversion will depend upon the extent of original construction modification required to achieve an acceptable configuration TOC Refrigeration, A/C and Heat Pumps Assessment Report

67 Again, conversion procedure definition by the original manufacturer is prudent and should be sought prior to decision to proceed. 3.4 End-of-Life Conservation and Containment Concerns Domestic refrigerators typically contain 50 to 250 grams of refrigerant. The small unit charge and the geographically dispersed location of these units complicate commercial opportunities to promote recovery and recycling initiatives to manage emissions from disposed units. Mandatory end-of-life refrigerant handling regulations have existed in many countries for several years. Chapter 11 of this report addresses this and related conservation approaches. 3.5 Current Refrigerant Use Domestic refrigeration annual refrigerant demand data are not reported but can be estimated using reasonable assumptions. Data required are historic annual unit production quantities, original equipment specified refrigerant and charge quantity information. Annual refrigerant demand for new equipment production has been calculated using this information and is summarised in Table 3-1. Field service refrigerant demand estimates are significantly less certain and have not been included for that reason New Equipment Production The conversion of domestic refrigeration original equipment manufacture to non-ods refrigerants is summarised in Table 3-1. Transition to non-ods refrigerants in original equipment manufacture is essentially complete. Sixty-three percent of current production uses HFC-134a refrigerant, 36% uses either HC-600a or an HC-600a/HC-290 blend and 1% uses other refrigerants, primarily HCFC-22 or HFC-152a TOC Refrigeration, A/C and Heat Pumps Assessment Report 55

68 Table 3-1 Estimated 1992 to 2008 Production of Domestic Refrigerators and Freezers by Refrigerant Type Global Region Year New Unit Production,Units New Unit Refrigerant Use, Tonnes CFC12 HFC134a HC600a 1 Other 2 Total CFC12 HFC134a HC600a 1 Other 2 TOTAL Weatern Europe Eastern Europe North America Central & South America Asia & Oceania Africa & Mid-East World Totals Footnotes: 1 Includes HC-600a + HC-290 blends 2 HCFC-22 and HFC-152a Field Service Data are not available to reasonably predict global refrigerant demand for field service. First order estimates with assumed service rates from industry service sources suggest 3 to 5 kilotonnes total annual demand. Approximately one-half of this demand is estimated to be ODS refrigerant to service legacy products in the field. The remaining demand is expected to be for non-ods refrigerants used to service products manufactured following new equipment production conversions. New product refrigerant service demand will be proportional to the various new product refrigerant demands. As mentioned above, transition from ODS refrigerants in non-article 5 countries was completed over 15 years ago. ODS service refrigerant demand in these countries is significantly reduced since the elapsed time following the conversion is comparable to the typical product life span. The limited residual ODS refrigerant service demand is served with recovered and recycled original charge refrigerant. Service blends are used where adequate recycled ODS refrigerant supply is not available or regulations preclude the use of ODS. The remaining majority of service demand is for non-ods refrigerants to service products produced after the transition from ODS refrigerants. This demand is served with newly manufactured refrigerant. Conversion of new equipment production to non-ods refrigerants in Article 5 countries occurred over a span of two to fifteen years ago. This later conversion extends the service transition issue in these countries. Service refrigerant demand is expected to continue to be for originally specified refrigerants: CFC-12 for legacy product and either HFC-134a or HC- 600a and HC-290 for new production. CFC-12 demand for product service will continue to be strong for another decade and then diminish over the subsequent decade. ODS refrigerants TOC Refrigeration, A/C and Heat Pumps Assessment Report

69 will continue to be used while they are available and economic. The dispersed and uncoordinated nature of the service industry limits opportunities to develop an effective recovery and recycling supply stream. Mandatory service regulations could promote use of drop-in replacement refrigerants and reduce emissions of ODS refrigerants Future Refrigerant Demand Implications Refrigerant demand for domestic refrigeration use is expected to continue to grow slowly, driven by product saturation increase in Article 5 countries and the growing number of global dwelling units. Two factors are anticipated to alter refrigerant selection and influence relative demands plus there is always the remote possibility for new developments to modify demand in a discontinuous manner. Second generation non-ods refrigerant migration from HFC-134a to HC-600a in new product production is occurring as a result of the GWP difference between the two alternatives. This migration began in Japan several years ago and was recently introduced on a limited basis in the United States. No new technology is required and the trend will likely proliferate. The rate and extent of proliferation will be influenced by the relative cost for HFC-134a and HFC-600a products. Current estimates indicate premium cost results from design changes to allow the use of flammable refrigerants in automatic defrost refrigerators. This suggests that voluntary migration across all product lines is not likely in countries with high litigation frequency. Second generation conversion from HC-600a/HC-290 blends to pure HC-600a could result from desires for improved product energy efficiency. No new technology would be required. Efficiency differences are small and controversial. Economic or energy efficiency drivers alone may not be sufficient to justify this conversion. Charging method simplification and compressor component standardisation for hydrocarbon usage are added benefit opportunities. The integrated implications of historic refrigerant demand are summarised in the refrigerant bank discussion in the Annex of this report /Pal03, Clo06, CEP09/. The 2006 update of these data continue to demonstrate domestic refrigeration bank growth. The data indicate an 11% typical 3-year growth rate for the bank in Article 5 countries and a 3% typical 3-year growth rate in non-article 5 countries. The aggregate domestic refrigerant bank in 2006 was estimated to be 153,000 tonnes: 40% CFC-12, 54% HFC-134a and 6% HC-600a. Approximately 53%of the bank resides in Article 5 countries and 47% resides in non-article 5 countries. The composition of the bank reflects growth of HFC and HC refrigerants and decline of CFC refrigerants, consistent with substitution of non-ods refrigerants for CFCs. An estimated 71% of residual CFCs in the bank reside in Article 5 countries Future Refrigerant Emission Implications The 2006 aggregate domestic refrigeration emissions, including end of life emissions, were estimated to be 9619 tonnes, or 6.8% of the total domestic refrigerant bank. Emissions were 77% CFC-12, 21% HFC-134a and 2% HC-600a. Since transition from use of CFC-12 in new production is complete, nearly all of the CFC emissions originate from the existing bank of legacy refrigerators. Geographic distribution of these emissions will be biased toward Article 5 countries since they hold the majority of the bank /CEP09/, have higher equipment repair rates /UNEP98/ and longer product lifetimes /CEP09/ TOC Refrigeration, A/C and Heat Pumps Assessment Report 57

70 The emissions trend to non-ods alternatives from the refrigerant bank is heavily damped. This sluggish response results from the 1500 to 1800 million unit installed base and long product life. Refrigerant systems are hermetically sealed during manufacture; and the majority of these units never require sealed system service. This intrinsic reliability results in emissions being dominated by end-of-life disposition. This suggests management of CFC-12 potential emissions from legacy refrigerators may be the largest domestic refrigeration opportunity for emission avoidance. 3.6 References /Bee08/ M. van Beek and M. Janssen, R-744 compared to R-290 in small freezer applications, 8 th IIR Gustav Lorentzen Conference on National Working Fluids, Copenhagen, /CEP09/ Domestic refrigeration refrigerant bank updated data through Authors, CEP, Ecole des Mines, December /Eur01/ Euromonitor International Inc. Global Appliance Information System, February 2009, /Eco06/ Eco-design requirements of EuP. Domestic Refrigerator and Freezer Directive Studies, July 2006, /EU09/ European Commission regulation (IEC) No. 643/2009 of 22 July 2009 implementing Directive 2005/32/EC of the European Parliament and of the Council with regard to ecodesign requirements for household refrigerating appliances. /IEC59M/ Performance of electrical household and similar cooling and freezing appliances. /SAE08/ SAE CRP1234, Industry Evaluation of Low Global Warming Potential Refrigerant HFO1234yf, (December 2008). /Tur07/ 2 nd International Workshop on Mobile Air Conditioning and Auxiliary Systems, Torino, Italy, HFO-1234yf: A Low GWP Refrigerant for MAC, (November 2007). /UNEP98/ UNEP 1998 Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee, Chapter 3, Domestic Refrigeration (1998 Assessment). /UNEP02/ UNEP 2002 Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee, Chapter 3, Domestic Refrigeration (2002 Assessment). UNEP06/ UNEP 2006 Report of the Refrigeration, Air Conditioning and Heat Pumps Technical Options Committee, Chapter 3, Domestic Refrigeration (2006 Assessment). /UNEP10/ UNEP Technology and Economic Assessment Panel Task Force Decision XXI/9 Report, Assessment of HCFC s and Environmentally Sound Alternatives Paragraph 2C, (May 2010). /Wes97/ Roy W. Weston Inc., Recycling Rate Determinant Study Phase 1 Report, Norcross, Georgia (1997) TOC Refrigeration, A/C and Heat Pumps Assessment Report

71 Chapter 4 Commercial Refrigeration Chapter Lead Author Denis Clodic Co-Authors Michael Kauffeld Peter Nekså Per-Henrik Pedersen Roberto Peixoto 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 59

72 4 Commercial Refrigeration 4.1 Introduction Commercial refrigeration is characterised by storing and displaying food and beverages at different levels of temperature within retail environments. The refrigerating capacities of equipment vary from some hundred Watts to 1.5 MW. Refrigerant choices are depending on the two main levels of temperatures necessary for the conservation of fresh food and beverages on one hand, and frozen food on the other hand. The more compact the equipment, the better the refrigerant containment. Centralised systems used in large supermarkets are the most emissive due to the large number of joints, expansion valves, and the possible failures due to oil return, corrosion, and vibrations. HCFC-22 represents still the largest refrigerant bank in commercial refrigeration and is used at all temperature levels.. Research and field tests have been carried out aiming at defining new technical options in order to use refrigerants with zero ODP and low GWP, to keep at least the same energy efficiency for the new systems, to improve their leak tightness, and to lower the refrigerant charges. 4.2 Application Equipment and Systems Commercial refrigeration is composed of three main categories of equipment: stand-alone equipment, condensing units, and supermarket systems. Stand-alone equipment consists of systems where all refrigeration components are integrated and, for the smallest types, the refrigeration circuit is entirely brazed or welded. Stand-alone equipment, including freezers, vending machines, and beverage coolers, are extensively used in many Article 5 countries. For developing countries, domestic refrigerating equipment, refrigerators and freezers can be found in small shops and are used for commercial purposes. Stand-alone equipment emits its refrigerant charge mainly at end of life when decommissioning, if no stringent recovery policy is in place and enforced. Condensing units exhibit refrigerating capacities ranging typically from 1 kw to 20 kw, they are composed of one (or two) compressor(s), one condenser, and one receiver assembled into a so-called condensing unit, which is located external to the sales area. The cooling equipment consists of one or more display case(s) in the sales area and/or a small cold room. Condensing units are typically installed in specialty shops such as bakeries, butcher shops, and convenience stores. In a number of small supermarkets, one can find a large number of condensing units (typically up to 20) installed side-by-side in a small machinery room. In most of the A5 countries, the use of systems employing condensing units is very extensive. Annual emission rates are estimated between 7 and 12%. Centralised systems are the preferred option in supermarkets. They operate with racks of compressors installed in a machinery room (see figure 4-1). A number of possible designs exist. Two main design options are used: direct and indirect systems. Direct systems are the most widespread. The refrigerant circulates from the machinery room to the sales area, where it evaporates in display-case heat exchangers, and then returns in vapour phase to the suction headers of the compressor racks. The supermarket cold rooms are cooled similarly TOC Refrigeration, A/C and Heat Pumps Assessment Report

73 Figure 4-1: Multiple compressor racks in machinery rooms for medium and low temperature display-cases / Clo08/ In the machinery room, racks of multiple compressors are installed with common suction and discharge lines, and each rack is usually associated with an air-cooled condenser. Specific racks are dedicated to low temperature and others to medium temperature. Each refrigerant circuit of each rack is independent. Supermarket centralised systems with long piping circuits have led to large refrigerant charges (100 to 3,000 kg depending on the size of the supermarket) and consequently led to large losses when ruptures occur. Some commercial companies have studied /Ets07/ and taken measures in order to limit refrigerant leaks; their report show how they reduce emissions from 25% annual emission level to about 12%. So the typical emission rates of small supermarkets vary between 15 and 25% and those of large supermarkets between 20 and 35%. These figures represent, in general, the non-article 5 situation. The emission rates for most of the Article 5 countries are much higher. Figure 4-2: Indirect system with MPG (Mono-propylene-glycol) at the medium temperature level and R-744 at the low temperature level / Clo08/ Indirect systems (see Figure 4-2) are composed of primary heat exchangers where a heat transfer fluid - HTF (also called secondary refrigerant) - is cooled and pumped to the display cases where it absorbs heat, and then comes back to the primary heat exchanger. HTFs have received much interest in recent years because indirect systems allow for a lower primary refrigerant charge and facilitate the use of flammable or toxic refrigerants when isolated from the sales area /Rhi09/. Other designs including the so-called distributed systems and hybrid systems have been developed (see section 4.5.3) TOC Refrigeration, A/C and Heat Pumps Assessment Report 61

74 4.2.2 Data on Outlets and stand-alone equipment Commercial refrigeration encompasses equipment installed in hotels, bars, restaurants, gas stations, train platforms, speciality shops (butchers, fishmongers, deli shops...), convenience stores and supermarkets. The sizes of the stores depend on opening hours, social habits, road infrastructure, and type of habitat. In 2006, the number of supermarkets world-wide is estimated at 280,000 covering a wide span of sales areas varying from 400 m 2 to 20,000 m 2 (among them 10,000 very large supermarkets with food sales areas varying between 2,000 and 5,000 m 2 ). Note: Available data are coming from marketing studies where the type of outlets is defined in different ways depending on the study. The data imply uncertainties on the level of refrigerating equipment especially in fast developing countries. World-wide in 2006, the number of mini-markets is estimated at 4 million where condensing units are mostly used. Condensing units are also used in many other stores; their number is estimated at 34 million units. The number of food retail stores is estimated at 9.8 million where stand-alone equipment and even domestic refrigerators and freezers are found. In 2006, the population of vending machines and other stand-alone equipment is evaluated at 20.5 and 32 million units, respectively. Based on those data, the refrigerant bank in 2006 was estimated at 340,000 MT and was distributed as follows: 46% in centralised systems; 47% in condensing units, and 7% in stand-alone equipment. The estimated sharing of refrigerants per type is about 15% CFCs, which are still in use in Article 5 countries, 62% HCFCs the dominant refrigerant bank and still for many years, and 23% HFCs that have been introduced in new equipment in Europe and Japan as of Note: In 2006, HCs mainly introduced in standalone equipment are not visible in terms of refrigerant bank. 4.3 Options for New Equipment Complementary to information on refrigerant choices, issues on energy conservation and energy efficiency will be briefly addressed in order to underline possible advantages and drawbacks of refrigerant choices on energy efficiency Stand-Alone Equipment The main families of stand-alone equipment are vending machines, ice makers, ice cream freezers, water fountains, and plug-in display cases. Part of stand-alone equipment such as wine-coolers, professional kitchen refrigerators and freezers, and hotel mini-bars, is based on the same technology as domestic refrigerators and freezers. Consequently the technical options of these series of equipment are analysed in Chapter 3, and similar trend of replacement of HFC-134a by hydrocarbons (HC-) is observed but for standalone equipment HC-290 is the refrigerant of choice rather than HC-600a TOC Refrigeration, A/C and Heat Pumps Assessment Report

75 Other types of stand-alone equipment have a specific design: water coolers, ice makers, vending machines, and display cases, and are covering also several levels of temperatures. For food and beverages kept at temperatures ranging from +1 C up to 10 C, HFC-134a is the dominant refrigerant, replaced by HC-600a and HC-290 in some families of equipment where generally the refrigerant charge is small lower than 150 g for most manufacturers even if some European brands commercialise equipment with Hydrocarbon charge up to 1 kg and even 2.5 kg depending on national regulation. For other companies R-744 is the preferred refrigerant choice. Ice Cream freezers For ice cream freezers, R-404A as well as HFC-134a has been the standard design since 1995; the switch from HFC refrigerant to propane (HC-290) is steady. The lifetime of the equipment is about 10 years, The estimated installed base using HC is of 500,000. Water Fountains Water fountains for both bottled water and tap water are installed in office buildings, supermarkets, etc. They are installed with a small compressor refrigeration system and so far HFC-134a is the most used refrigerant. Typical HFC-134a charge is about 40 g. Some companies are now introducing HC-600a with refrigerant charge as low as 20 g and the market share of those HC systems is growing. 25% of the installed base in 2010 is estimated to be using HC-600a taking into account a life time of 10 years and knowing the current policies of the large global companies. Ice Machines A large number of ice machines are installed in restaurants, bars, and hotels. Several sizes are available and refrigeration capacities vary from 1 to 10 kw, with refrigerant charge varying accordingly from some hundred grams to 1 kg. Company policies as well as country regulations will lead to different refrigerant choices: HFC-134a, hydrocarbons and possibly R-744. So far, HFC-134a is globally the dominant choice. Vending Machines The cooling capacity of vending machines is about 600 W for rapid cooling of cans. HFC- 134a is the standard refrigerant in vending machines. One global company has chosen R-744 as a refrigerant. This new R-744 system is installed inside a plug-in/pull-out cassette and its energy efficiency, as measured, is as good as the reference HFC systems up to 32 C ambient temperature. One global company has taken the commitment that all new equipment will be HFC free as of Several others are following the same path. R600a appliances have also been developed, but its application is limited to certain styles of construction.r-744 and HC vending machines are taking a significant market share in Japan. One OEM has developed a not-in-kind Stirling refrigeration prototype for vending machines. The energy efficiency of this new system was better than the reference vapour compression base line, but the cost was considered too high by customer companies and so this system did not reach the market. Glass-Door Coolers Glass-door bottle coolers can be found in supermarkets, convenience stores, gas stations etc. The most common type is the one-door 400-litre-type. Glass-door coolers are often installed by a soft drink company TOC Refrigeration, A/C and Heat Pumps Assessment Report 63

76 Currently, HFC-134a is the standard choice. Since 2000, several thousand units have been installed in Europe using mostly HC-600a and, for some brand names, HC-290. Some global companies have rather chosen R-744 systems for their bottle coolers. Plug-in Display Cabinets The use of plug-in display cabinets is increasing in small and medium size supermarkets. This choice is made because plug-in cabinets are cheaper and more flexible than remote display cabinets connected to a centralised system. In warm climate countries and in general during the hot season, the heat released by the condenser of each and every plug-in cabinet in the sales area has to be removed by an air-conditioning system, which has to be designed with a significant larger cooling capacity. On the other hand, in colder climates such as Northern Europe, the heat rejected by the condenser and compressor is useful in heating the store and can be regarded as heat recovery in the cold season. So far, R-404A refrigerant is the standard choice, and the charge per unit varies from 220 g up to 3 kg. Especially in Germany, UK and the Northern European countries plug-in display cabinets running on HC-290 are gaining market share. Several German supermarket chains only purchase HC plug in cabinets /Rhi09/. There has been conversion of production facilities from HCFC and HFC to HC for standalone commercial refrigeration equipment in Article 5 countries for the domestic market /GTZ09i/. In many Article 5 countries, even in large supermarkets, plug-in cabinets are preferred to remote cabinets connected to a centralised system. The evident drawback is that plug-in cabinets are releasing all heat inside the sales area and either the AC system has to be designed in order to absorb this additional heat load or the temperature inside the supermarket can reach very high values (above 30 C and sometimes above 40 C) leading to a poor capability of plug-in cabinets to keep the products at the right temperature. Moreover, the overall energy efficiency of supermarkets using plug-in cabinets is low due to the fact that the energy efficiency of small motor-compressors is lower than medium and large size compressors. For all stand-alone equipment, energy conservation standards can be and are being issued or revisited because laboratory tests can be performed in order to assess refrigerating capacities and electric input power, and so establishing equipment energy efficiency. The base line energy consumption can be established, engineering analyses can be performed, and improvements can be targeted. Regulations as well as electricity costs are the drivers for significant improvements of energy efficiency, the market being driven by initial costs so far. It is estimated that all refrigerants banked in stand-alone equipment represent an amount of about 38,000 tonnes, emission levels during the lifetime is estimated from 1 to 5 % depending on servicing quality, corrosion and day to day handling of goods. Due to the compact refrigeration circuit, leaks at the beginning of the life cycle of the equipment are well handled; the number of joints being minimal or even nil (all brazed or welded circuit). The critical issues are related to corrosion, equipment day-to-day handling, and aggressive cleaning leading to possible circuit ruptures. Emissions occur essentially at end of life decommissioning. In summary, HFC-134a fulfils the technical constraints in terms of reliability and energy performance for stand-alone equipment. In many developed countries GWP of HFC-134a is more and more considered as prohibitive in relation to refrigerant emissions, so HC refrigerants and R-744 are gaining significant market shares in Europe and Japan. In the near future, unsaturated HFC such as HFC-1234yf could be considered as an option, the retrofit from HFC-134a to this new refrigerant expected as being rather simple even if long-term reliability has to be assessed /See 10/ TOC Refrigeration, A/C and Heat Pumps Assessment Report

77 4.3.2 Condensing Unit Systems Condensing units are found in many convenience stores and food specialist stores for cooling a small cold room and one or several display cases. The technology can be considered as a mass production one with usually hermetic compressors, sometimes semi-hermetic ones. Condensing unit is a well spread option in Article 5 countries. Even in supermarkets, especially in some Article 5 countries, several racks of condensing units are installed side-byside in small machinery rooms. Condensing units are less energy efficient, compared to a well-designed small-centralised system but condensing units are chosen for initial cost reasons, easiness of installation, and are found ready to install. The cooling capacity varies from 1 to 20 kw mostly at medium temperature and the refrigerant charge varies from 1 to 5 kg for HCFCs or HFCs. HCFC-22 is still the most used refrigerant in the U.S. and in all Article 5 countries. New equipment can use HFC-134a, HCFC-22, R-404A, R-407C, R-507, R-410A other HFC and HCFC blends, HC refrigerants and R-744. HFC-134a, HCFC-22 and R-404A are the dominant refrigerants. In Europe, due to the E.U. regulation, a shift from HCFC-22 to R-404A or sometimes R-507A has occurred as of R-404A is the leading choice also for cost reasons; the condensing units using this refrigerant are cheaper compared to HFC-134a units of the same cooling capacity because of smaller compressor. Nevertheless in hot climate and for medium temperature applications, HFC-134a is used due to its better energy performances at high ambient temperatures compared to R-404A. Condensing units are always designed as direct expansion systems, and so their environmental impacts are related to refrigerant choice and energy efficiency. What is described for stand-alone equipment is also verified for condensing units when the units are replacing larger compressors. As stated previously, this non-efficient solution in terms of energy consumption is chosen due to investment cost reasons and to the availability of condensing units everywhere in the world. Moreover, these condensing units are also produced in large series in Article 5 countries avoiding the import of large size compressors Supermarket Systems Centralised systems For large supermarkets, the dominant design is the so-called centralised system where all the compressor racks are installed in a single machinery room. This concept has led to the installation of up to several kilometres of piping, containing refrigerant in liquid phase from the machinery room to the sales area and refrigerant in vapour phase back from the sales area to the machinery room. The size of centralised systems can vary from refrigerating capacities of about 20 kw to more than 1 MW related to the size of the supermarket. The refrigerating capacities are generated by independent racks of compressors at two main levels of evaporating temperatures -40 / -35 C for frozen food (and ice-creams) and -15 / - 10 C for fresh food (dairy, meat etc.). Low-temperature racks represent about 10 to 30% of the refrigerating capacities and so the medium-temperature racks represent 70 to 90% of the total refrigerating capacities. In terms of energy consumption, the low-temperature racks consume 20 to 35% of the total energy consumption due to lower energy efficiency related to the level of temperature. The refrigerant charges are related to the refrigerating capacity and store layout. For large supermarkets (food sales area larger than 3,000 m 2 ) with current direct expansion centralised systems, the refrigerant charge varies from 800 kg to 2 tonnes TOC Refrigeration, A/C and Heat Pumps Assessment Report 65

78 Heat recovery for heating the store typically requires a 4-way valve on each condensing circuit and also dedicated heat exchangers in order to recover the condensation capacity during the heating season; this energy is usually released to the environment by the air cooled condensers. This possible design is popular in cold regions in the USA and in some European countries,. The circuit is more complicated, the refrigerant charge is higher by at least 20%. This technical option has to be studied in terms of return on investment, level of refrigerant emissions and servicing. For moderate and hot climates this option is not selected due to the added complexity and the low heating needs that hamper the return on investment. Other simpler designs are found in Europe, especially in the northern countries where domestic hot water is produced by de-superheating the refrigerant before entering the condenser. A new system design mostly introduced in small supermarkets integrates the cooling / heating system of the shop with the refrigeration system, making an interesting example of a holistic approach for energy management. In order to simplify servicing in the current centralised design, most of the commercial companies, except in Japan, has chosen to use the same refrigerant at the two levels of temperatures. This choice is arguable because as an example HFC-134a or R-407C and R- 717 are more efficient as refrigerants at the medium-temperature level compared to R-404A and on the contrary R-404A or R-744 are the most efficient refrigerants at the lowtemperature level. As always the design of the system defines the effective energy efficiency and so efficient design can be found even with a less efficient refrigerant. Nevertheless, in terms of choice of refrigerant, one can keep in mind that refrigerants could be different for the medium-temperature level and for the low-temperature level giving a larger number of technical options when environmental impacts of refrigerants have to be limited. One of the major consequences of making separate choices for refrigerants dedicated to the low-temperature and to the medium-temperature is that R-744 can be the preferred choice at the low-temperature level in a cascade design and the choice for the medium-temperature level is under evaluation in developed countries depending on global warming, costs, and easiness of use. In parallel to refrigerant evaluation, technical options have been developing since nearly 15 years in order to lower the refrigerant charge by the development of indirect systems and distributed systems. Distributed Systems This technical alternative has been studied and realised as of The concept is to install the compressors close to the display cases either inside or very close to the sales area. Figure 4-3: Distributed system where a single package refrigerating system provides refrigeration to a series of display cases / Clo08/ This design is more practical for the typical US layout of supermarkets where most of the medium-temperature display cases are installed near by the walls and not in aisles, as it is usual in Europe. The reference design of distributed system integrates water condensers in a TOC Refrigeration, A/C and Heat Pumps Assessment Report

79 soundproof box with the compressor(s). The water, used as a coolant in the condensers, is cooled usually by roof-mounted dry coolers. The refrigerant charge can be reduced by more than 50% and up to 75%. While at the same time leakage rates are reduced due to fewer joints. The energy efficiency of such a system has to be carefully analysed. Energy gains can be made due to the huge reduction of piping length and thereby reduced pressure losses, but the compressors are smaller and so their energy efficiencies are usually lower. Moreover, an additional difference of temperature is created when using water-cooled condensers that are releasing their heat in air-dry coolers. The complexity of the comparison between the baseline (centralised system) and the new distributed system is enhanced when changing the refrigerant (HFCs, HCs, or R-744 compared to R-22); so a wide variation of performances can be found in the technical literature. Distributed systems are still not a widespread option and are mainly installed in new US supermarkets with HFC refrigerants. It has to be noted that indirect-distributed systems have been developed in UK. The system uses hydrocarbon as a refrigerant and a heat transfer fluid for transferring heat from the display cases to the evaporator. Indirect Systems Indirect systems represent a small market share of new installations and they replace direct expansion centralised systems in supermarkets. This option has been developed in Europe as of 1995 and has expanded initially slowly. It has to be noticed that several US commercial chains have decided since 2006 to install indirect systems. The driver to change from usual direct expansion systems is the significant reduction of refrigerant charges (50 to 85 %) and a much better refrigerant containment. Depending on the country, R-404A or R-507, sometimes R-717, HCs (HC-290 or HC-1270), and R-744 are used as primary refrigerants in the refrigerating system entirely installed in the machinery room. Due to high latent heat of vaporisation and low liquid density, the ammonia (R-717) charge can be 10% of the usual HFC refrigerant charge. Such systems can be installed in special machinery rooms with safety features allowing high ventilation rates in case of significant leaks. The same applies to HC refrigerants with charge typically 10% of the direct system HFC reference charge. For safety reasons, the refrigerant circuits are separated in several independent ones, limiting the refrigerant charge of each system /IPCC05/. Many indirect systems have been designed, still using R-404A as primary refrigerant in the machinery room, the reduction of the charge yields to significant reduction of the environmental impact. Well-designed indirect systems can be as efficient as well-designed direct systems due to better heat exchange in the air coils, but heat transfer fluids (HTF) such as mono-propyleneglycol (MPG) used in indirect systems need special attention, especially at low temperatures where pumping power may be excessive. Alternative HTFs exist which have lower viscosity at low temperatures. Nonetheless, indirect systems are nowadays mainly built for the Medium Temperature range. Also the pumps have to be carefully chosen in order to avoid significant additional energy consumption. For indirect systems, R-744 as HTF is mainly used in low-temperature display cases and cold rooms. R-744 is partially evaporated in the display-case evaporators, returns in two-phase flow to the primary evaporator in the machinery room, where R-744 is fully condensed or liquefied, and then pumped back to the display cases. Such design is energy efficient 2010 TOC Refrigeration, A/C and Heat Pumps Assessment Report 67

80 because there is no superheat zone at the exit of each evaporator. The only threat for indirect systems using R-744 is the possible release of the entire R-744 charge related to a lack of cooling due to an incident on the refrigerating system. The R-744 pressure increases progressively with the lack of cooling and is related to the temperature in the circuit. If the safety valve is set around 3 MPa (which is usual), the opening of the safety valve will occur when the temperature of the coldest part of the system is about 5 C leading to a release of R-744. More generally, indirect systems are linking all cooling elements one to the others, which in case of a significant failure leads to the complete loss of refrigeration and the possible loss of food. The current multiple-rack centralised system offers the possibility of limiting the incident on a single rack, the other ones being capable to provide the complementary cooling during the repair. Special charge limitation rules have led to a similar design for indirect systems in Sweden. Namely racks of individual refrigeration systems, all cooling the same indirect loop. Up to 20 such racks are installed in large Swedish supermarkets. One German discount chain has announced that they will only purchase indirect hydrocarbon systems for their new supermarkets. A drawback of indirect systems is related to the necessary insulation of all piping in order to avoid humidity condensation and icing. Valves and pumps can present difficulties for efficient insulation and may become ice blocks with water dripping continuously around the ice blocks; moreover, for liquid HTF used at the medium-temperature level, quantities are enormous representing several metric tonnes, and possible leaks of HTF are difficult to diagnose especially in the display cases. All those lessons learnt from the existing indirect systems are to be tackled by improved designs. Hybrid and Cascading Systems Hybridisation between direct and indirect systems can be found in the current technical offerings (one example is shown in figure 4-4) with a limited additional cost if any. Figure 4-4: Hybrid system comprising a R-744 cascade at the low temperature level and a secondary system at the medium temperature level / Clo08/ TOC Refrigeration, A/C and Heat Pumps Assessment Report